(A.  J*    \j 


'The  most  perfect  system  of  rules  to  insure  success  must 
be  interpreted  upon  the  broad  grounds  of  professional  intelli- 
gence and  common  sense." 


GENERAL  SPECIFICATIONS 

FOR 

Iron  and  Steel  Railroad  Bridges 

AND    VIADUCTS. 


NEW    AND     REVISED     EDITION, 
189O. 


By  THEODORE  COOPER, 

Consulting  Engineer. 

ENGINEERING  NEWS  PUBLISHING  COMPANY, 

TRIBUNE    BUILDING,    NEW    YORK. 


OF  THE 


AMERICAN  RAILROAD  BRIDGES, 


By  THEODORE  COOPER,  M.  Am.  Soe.  C.  E., 

Reprinted  from  the  Transactions  of  American  Society  of  Civil  Engineers . 


PRICE. 


60  pages,  8vo.,  cloth.  18  Folding  Plates;  8  page  illustrations 
by  Phototype  process;  Appendix  giving  Abstract  of  Recent 
Tests  on  full  size  Bridge  Members,  -  -  $2  OO 


Specifications  for  Iron  and  Steel  Railroad  Bridges,     $O   25 

Highway       "  25 


ENGINEERING  NEWS  PUBLISHING  COMPANY, 

Tribune  Building,  New  York. 


• 

UN, 


Copyright  by  THEODORE  COOPER, 

Consulting  Engineer,  35  Broadway,  New  York. 


General  Specifications  for  Iron  and  Steel 
Railroad  Bridges  and  Viaducts, 


NEW  AND  REVISED  EDITION. 
1890. 


GENERAL    DESCRIPTION. 

1.  All  parts  of  the  structures  shall  be  of  wrought-iron  or 
steel,  except  ties  and  guard  rails.    Cast-iron  or  steel  may  be 
used  in  the  machinery  of  movable  bridges  and  in  special 
cases  for  bed-plates. 

2.  The  following  kinds  of  girders  shall  preferably  be  em- 
ployed : 

Spans,  up  to    16  feet Boiled  beams.  Bridges. 

"  16  to    70    "    Riveted  plate  girders. 

"  70  to  100    "     Riveted  plates  or  lattice  girders. 

"  over  loo    "    Pin-connected  trusses. 

Generally  "double  tracks  through''  bridges  will   have 
but  two  trusses,  to  avoid  spreading  the  tracks  at  bridges. 

In  calculating  strains  the  length  of  span  shall  be  under- Length  of  spau. 
stood  to  be  the  distance  between  centres  of  end  pins  for 
trusses,  and  between  centres  of  bearing  plates  for  all  beams 
and  girders. 

3.  The  girders  shall  be  spaced,  with  reference  to  the  axis  gpjSjJJg  of 
of   the   bridge,    as   required    by  local   circumstances,   and 
directed  by  the  Engineer  of  the  Railroad  Company.     (§  5.) 
Longitudinal  floor  girders  shall  in  no  case  be  less  than  three 

feet  and  three  inches  from  centre  line  of  tracks.     (§  6.) 

4.  For  all  through  bridges  and  overhead  structures  there  Head-room, 
shall  be  a  clear  head-room  of  20  feet  above  the  base  of  the 

rails. 

5.  In  all  through  bridges  the  clear  width  from  the  centre ciear  width, 
of  the  track  to  any  part  of  the  trusses  shall  not  be  less  than 


seven  (7)  feet  at  a  height  exceeding  one  foot  above  the  rails 
where  the  tracks  are  straight,  and  an  equivalent  clearance 
shall  be  provided  where  the  tracks  are  curved. 

6.  The  standard  distance,  centre  to  centre  of  tracks  on 
straight  lines,  will  be  thirteen  (13)  feet. 

Treetie  Towers.  ^  Each  trestle  bent  shall,  as  a  general  rule,  be  composed 
of  two  supporting  columns,  and  the  bents  united  in  pairs  to 
form  towers ;  each  tower  thus  formed  of  four  columns  shall 
be  thoroughly  braced  in  both  directions.  Transversely  the 
column  shall  have  a  uniform  batter  sufficient  to  nearly  or 
quite  prevent  tension  at  the  base  under  the  greatest  wind 
force  specified,  either  during  erection  or  after  completion. 

8.  Each  tower  shall  have  sufficient  base,  longitudinally, 
to  be  stable  when  standing  alone,  without  other  support 
than  its  anchorage.  (§§  25,  26.) 

Trestle  spans.  9>  Tower  spans  for  high  trestles  shall  not  be  less  than  30 
feet ;  intermediate  spans  about  60  feet. 

Form  of  Trusses  lOf  Unless  otherwise  specified  the  form  of  bridge  trusses 
may  be  selected  by  the  bidder  ;  but  to  secure  uniformity  in 
appearance  it  is  desired  that  all  "  through  "  trusses  shall  be 
built  with  inclined  end  posts ;  for  pin-connected  trusses, 
preference  shall  be  given  to  those  of  single  intersections. 

ii.  All  "deck"  trusses  shall  have  top  chord  bearings  at 
abutments,  which  are  retaining  walls,  unless  otherwise  or- 
dered for  particular  structures. 

wooden  rioor.  I2  xne  WOoden  floors  shall  consist  of  transverse  ties  or 
floor  timbers ;  their  scantling  will  vary  in  accordance  with 
the  design  of  the  supporting  iron  floor.  (§  15.)  They  shall 
be  spaced  with  openings  not  exceeding  six  inches,  and  shall 
be  secured  to  the  supporting  girders  by  |-inch  bolts  at  dis- 
tances not  over  six  feet  apart.  For  deck  bridges  the  ties 
will  extend  the  full  width  of  the  bridge,  and  for  through 
bridges  at  least  every  other  tie  shall  extend  the  full  width 
of  bridge  for  a  footwalk. 

Guard  Timbers.  1$.  There  shall  be  a  guard  timber  (scantling  not  less  than 
6  x  8")  on  each  side  of  each  track,  with  its  inner  face  parallel 
to  and  not  less  than  3  feet  3  inches  from  centre  of  track. 
Guard  timbers  must  be  notched  one  inch  over  every  floor 
timber,  and  be  spliced  over  a  floor  timber  with  a  half-and- 


3 

half  joint  of  four  inches  lap.  Each  guard  timber  shall  be 
fastened  to  every  third  floor  timber  and  at  each  splice  with 
a  three-quarter  (f )  inch  bolt. 

14.  The  guard  and  floor  timbers  must  be  continued  over 
all  piers  and  abutments. 

15.  The  maximum  strain  allowed  upon  the  extreme  fibre 
of  the  best  yellow  pine  or  white  oak  floor  timbers  will  be 
800  pounds  per  square  inch.     The  weight  of  a  single  engine 
wheel  being  assumed  as  distributed  over  three  ties  spaced 
as  per  §  12. 

1 6.  The  floor  timbers  from  centre  to  each  end  of  span 
must  be  notched  down  over  longitudinal  girders  so  as  to 
reduce  the  camber  in  the  track,  as  directed  by  the  Engineer. 

17.  All  the  floor  timbers  shall  have  a  full  and  even  bear- 
ing upon   the   stringers;  no  open  joints  or  shims  will  be 
allowed. 

1 8.  On  curves  the  outer  rail  must  be  elevated,  as  may  be 
directed  by  the  Engineer. 

19.  In  comparing  different  proposals,  the  relative  cost  topr°p°8als- 
the  Railroad  Company  of  the  required  masonry  or  changes 

in  existing  work  will  be  taken  into  consideration. 

20.  Contractors   in   submitting   proposals    shall    furnish 
complete  strain    sheets,   general    plans    of    the    proposed 
structures,  and  such  detail  drawings  as  will  clearly  show 
the  dimensions  of  all  the  parts,  modes  of  construction,  and 
the  sectional  areas. 

21.  Upon  the  acceptance  of  the  proposal  and  the  execu- 
tion of    contract,  all  working  drawings  required   by   the 
Engineer  must  be  furnished  free  of  cost. 

22.  No  work  shall  be  commenced  or  materials  ordered  Approval  of 
until  the  working  drawings  are  approved  by  the  Engineer 

in  writing;  if  such  working  drawings  are  detained  more 
than  one  week  for  examination,  the  Contractor  will  be 
allowed  an  equivalent  extension  of  time. 

LOADS. 

23.  All  the  structures  shall  be  proportioned  to  carry  the 
following  loads : 

ist.  The  weight  of  iron  in  the  structure.     2d.  A  floor 


weighing  400  pounds  per  linear  foot  of  track,  to  consist  of 
rails,  ties,  and  guard  timbers  only. 

These  two  items,  taken  together,  shall  constitute  the 
"dead  load." 

3d.  For  class  Lehigh  Heavy  Grade  Engine — A  moving 
load  for  each  track,  supposed  to  be  moving  in  either  direc- 
tion, and  consisting  of  two  "  consolidation ''  engines 
coupled,  followed  by  train  weighing  4,000  pounds  per  run- 
ning foot.  This  "live  load"  being  concentrated  upon 
points  distributed  as  in  Diagram  No.  i.  Or,  100,000  pounds 
equally  distributed  upon  two  pairs  of  drivers,  seven  feet 
centre  to  centre  ;  or, 

3d.  For  class  Extra  Heavy  A — A  moving  load  for  each 
track,  supposed  to  be  moving  in  either  direction,  and  con- 
sisting of  two  "  consolidation  "  engines  coupled,  followed 
by  train  weighing  3,000  pounds  per  running  foot.  This 
"  live  load  "  being  concentrated  upon  points  distributed  as 
in  Diagram  No.  2.  Or,  80,000  pounds  equally  distributed 
upon  two  pairs  of  drivers,  seven  feet  centre  to  centre ;  or, 

3d.  For  class  A — A  moving  load  for  each  track,  supposed 
to  be  moving  in  either  direction,  and  consisting  of  two 
' '  consolidation  "  engines  coupled,  followed  by  train  weigh- 
ing 3,000  pounds  per  running  foot.  This  "  live  load  "  being 
concentrated  upon  points  distributed  as  in  Diagram  No.  3. 
Or,  80,000  pounds  equally  distributed  upon  two  pairs  of 
drivers,  seven  feet  centre  to  centre ;  or, 

3d.  For  class  B — A  moving  load  for  each  track,  supposed 
to  be  moving  in  either  direction,  and  consisting  of  two 
"  consolidation  "  engines  coupled,  followed  by  train  weigh- 
ing 2,240  pounds  per  running  foot.  This  "  live  load  "  being 
concentrated  upon  points  distributed  as  in  Diagram  No.  4. 
Or,  80,000  pounds  equally  distributed  upon  two  pairs  of 
drivers,  seven  feet  six  inches  centre  to  centre  ;  or, 

3d.  For  class  C — A  moving  load  for  each  track,  supposed 
to  be  moving  in  either  direction,  and  consisting  of  two 
"  mogul ''  engines  coupled,  followed  by  train  weighing 
2,000  pounds  per  running  foot.  This  "  live  load  "  being 
concentrated  upon  points  distributed  as  in  Diagram  No.  5. 
Or,  80,000  pounds  equally  distributed  upon  two  pairs  of 
drivers,  eight  feet  centre  to  centre. 


Diagram 
No.  1. 

Diagram 
No.  2. 

Diagram 
No.  3. 

Diagram 
No.  4 

Diagram 

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The  maximum  strains  due  to  all  positions  of  either  of  the 
above  "live  loads,"  of  the  required  class,  and  of  the  "  dead 
load,"  shall  be  taken  to  proportion  all  the  parts  of  the  struc- 
ture. 

24.  To  provide  for  wind  strains  and  vibrations,  the  top 
lateral  bracing  in  deck  bridges,  and  the  bottom  lateral  brac- 
ing in  through  bridges,  shall   be  proportioned  to  resist  a 
lateral  force  of  450  pounds  for  each  foot  of  the  span ;  300 
pounds  of  this  to  be  treated  as  a  moving  load. 

The  bottom  lateral  bracing  in  deck  bridges,  and  the  top 
lateral  bracing  in  through  bridges,  shall  be  proportioned  to 
resist  a  lateral  force  of  1 50  pounds  for  each  foot  of  the  span. 

Preference  will  be  given  to  lateral  bracing  in  the  floor 
system,  which  is  capable  of  resisting  both  compression  and 
tension. 

25.  In  trestle  towers  the  bracing  and  columns  shall  be 
proportioned  to   resist  the  following   lateral  pressures,  in 
addition  to  the  strains  from  dead  and  live  loads : 

ist.  The  trusses  fully  loaded,  a  lateral  pressure  at  the 
level  of  the  tracks,  of  650  pounds  for  each  longitudinal 
lineal  foot  of  the  structure;  and  a  lateral  pressure  of  125 
pounds  for  each  vertical  lineal  foot  of  the  trestle  bents ;  or, 

2d.  The  trusses  unloaded,  a  lateral  pressure,  at  the  level 
of  the  tracks,  of  600  pounds  for  each  longitudinal  lineal  foot 
of  the  structure ;  and  a  lateral  pressure  of  225  pounds  for 
each  vertical  lineal  foot  of  the  trestle  bents. 

26.  Longitudinally  the  bracing  of  the  trestle  towers  and 
the  attachments  of  the  fixed  ends  of  all  trusses  shall  be 
capable  of   resisting    the    greatest    tractive    force   of  the 
engines,  or  any  force  induced  by  suddenly  stopping  upon 
any  part  of  the  work  the  assumed  maximum  trains  ;  the  co- 
efficient of  friction  of  the  wheels  upon  the  rails  being  as- 
sumed as  0.20. 

27.  Variations  in  temperature,  to  the  extent  of  150  de- 
grees, shall  be  provided  for. 

28.  When  the  structures  are  on  curves,  the  additional 
effects  due  to  the  centrifugal  force  of  trains  moving  at  high 
velocities  shall  be  considered. 


29.  All  parts  shall  be  so  designed  that  the  strains  coming 
upon  them  can  be  accurately  calculated. 

PROPORTION  OF   PARTS. 

The  following  clauses  are  all  intended  to  apply  to  wrought- 
iron  construction. 

30.  All   parts  of  the  structure  shall   be  proportioned  in  Tensile  strain, 
tension  by  the  following  allowed  unit  strains : 

Pounds  per 
square  inch. 

Floor  beam  hangers,  and  other  similar  members 
liable  to  sudden  loading  (bar  iron  with  forged 
ends) _ 6,000 

Floor  beam  hangers,  and  other  similar  members 
liable  to  sudden  loading  (plates  or  shapes),  net 
section $  ,000 

Lateral  bracing __ 15 ,000 

Solid  rolled  beams,  used  as  cross  floor  beams  and 

stringers 8,000 

Bottom  flanges  of  riveted  cross  girders,  net  section        8,000 

Bottom  flanges  of  riveted  longitudinal  plate  gird- 
ers, over  20  feet  long,  used  as  track  stringers, 
net  section _. 8,000 

Bottom  flanges  of  riveted  longitudinal  plate  gir- 
ders, under  20  feet  1  ong,  net  section _  7,000 

For  For 

live  loads.        dead  loads. 

Bottom  chords,  main  diagonals,  counters 

and  long  verticals  (forged  eye-bars)  8,000  16,000 

Bottom  chords  and  flanges,  main  diago- 
nals, counters  and  long  verticals 
(plates  or  shapes),  net  section 7>5oo  1 5,000 

For  swing  bridges  and  other  movable  structures,  the  dead 
load  unit  strains,  during  motion,  must  not  exceed  three- 
fourths  of  the  above  allowed  unit  strains  for  dead  load  on 
stationary  structures. 

The  areas  obtained  by  dividing  the  live  load  strains  by 
the  live  load  unit  strains  will  be  added  to  the  areas  ob- 
tained by  dividing  the  dead  load  strains  by  the  dead  load 


Net  Section. 


Compressive 
Strains. 


8 

unit  strains  to  determine  the  required  sectional  area  of  any 
member.     (§  45.) 

31.  Angles  subject   to  direct  tension  must  be  connected 
by  both  legs,  or  the  section  of   one  leg  only  will  be  con- 
sidered as  effective. 

32.  In  members  subject  to  tensile  strains  full  allowance 
shall  be  made  for  reduction  of  section  by  rivet-holes,  screw- 
threads,  etc. 

33.  Compression  members  shall  be  proportioned  by  the 
following  allowed  unit  strains  : 

Chord  segments  P=  8,000 — 30 —  for  live  load  strains. 


Struts. 


All  posts 


P=  1 6,000 — 60 — for  dead  load  strains. 
P=7,ooo— 40 — for  live  load  strains. 


14,000 — 80 — for  dead  load  strains. 


10,500—60 — for  wind  strains. 
r 


P=9,ooo — 50 — for  assumed  initial  strain. 


Lateral  struts 

(§  340 

P=the  allowed  compression  per  square  inch  of  cross- 
section. 

Z=the  length  of  compression  member,  in  inches. 

R=ihe  least  radius  of  gyration  of  the  section,  in  inches. 

No  compression  member,  however,  shall  have  a  length 
exceeding  45  times  its  least  width. 

For  swing  bridges  and  other  movable  structures,  the 
dead  load  unit  strains  during  motion  must  not  exceed  J  of 
the  above  allowed  unit  strains  for  dead  load  on  stationary 
structures. 

34.  The  lateral  struts  shall  be  proportioned  by  the  above 
formula  (§  33)  to  resist  only  the  resultant  due  to  an  assumed 
initial  strain  of  10,000  pounds  per  square  inch  upon  all  the 
rods  attaching  to  them,  assumed  to  be  produced  by  adjusting 
the  bridge  or  towers.  (§  41.) 


9 

35-  In  beams  and  plate  girders  the  compression 
shall  be  made  of  same  gross  section  as  the  tension  flanges. 

36.  Riveted  longitudinal  girders  shall  have,  preferably,  a 
depth  not  less  than  T\  of  the  span. 

Rolled  beams  used  as  longitudinal  girders  shall  have,  pre- 
ferably, a  depth  not  less  than  y1^  of  the  span. 

37.  Members  subject  to  alternate  strains  of  tension  and 
compression  shall  be  proportioned  to  resist  each  kind  of 
strain.     Both  of  the  strains  shall,  however,  be  considered  as 
increased  by  an  amount  equal  to  -f^  of  the  least  of  the  two 
strains,   for  determining  the  sectional  areas  by  the  above 
allowed  unit  strains.     (§§  30,  33.) 

38.  The  strains  in  the  chords  and  end  posts  from  the  as-Effectofwind 

on  Chord 

sumed    wind   forces  need   not  be   considered,    except    asstrains- 
follows  : 

ist.  When  the  wind  strains  on  any  member  exceed  one- 
quarter  of  the  maximum  strains  due  to  the  dead  and  live 
loads  upon  the  same  member.  The  section  shall  then  be 
increased  until  the  total  strain  per  square  inch  will  not 
exceed  by  more  than  one-quarter  the  maximum  fixed  for 
dead  and  live  loads  only. 

2d.  When  the  wind  strain  alone  or  in  combination  with  a 
possible  temperature  strain,  can  neutralize  or  reverse  the 
tension  in  any  part  of  the  lower  chord. 

39.  The  rivets  and  bolts  connecting  the  parts  of  any  mem-  Rivets,  Bolts 
ber  must  be  so  spaced  that  the  shearing  strain  per  square"1 

inch  shall  not  exceed  7,500  pounds,  or  f  of  the  allowed  strain 
per  square  inch  upon  that  member;  nor  the  pressure  upon 
the  bearing  surface  per  square  inch  of  the  projected  semi- 
intrados  (diameter  X  thickness  of  piece)  of  the  rivet  or  bolt 
hole  exceed  12,000  pounds,  or  one  and  a  half  times  the  allowed 
strain  per  square  inch  upon  that  member.  In  the  case  of 
field  riveting  the  above  limits  of  shearing  strain  and  pressure 
shall  be  reduced  one-third  part.  Rivets  must  not  be  used 
in  direct  tension. 

40.  Pins  shall  be  so  proportioned  that  the  shearing  strain 
shall  not  exceed  7,500  pounds  per  square  inch;  nor  the  crush- 
ing strain  upon  the  projected  area  of  the  semi-intrados  of 
any  member  (other  than  forged  eye-bars,  see  article  79)  con- 


10 


Combined 
Strains. 


Plate  Girders, 
etc. 


Web  Plates. 


Boiled  Beams. 


nected  to  the  pin  be  greater  per  square  inch  than  12,000 
pounds,  or  one  and  a  half  times  the  allowed  strain  per 
square  inch  ;  nor  the  bending  strain  exceed  15,000  pounds 
per  square  inch  when  the  centres  of  bearings  of  the  strained 
members  are  taken  as  the  points  of  application  of  the  strains. 

41.  In  case  any  member  is  subjected  to  a  bending  strain 
from  local   loadings,  such   as    distributed    floors    on  deck 
bridges,  in  addition  to  the  strain  produced  by  its  position  as 
a  member  of  the  structure,  it  must  be  proportioned  to  resist 
the  combined  strains. 

If  the  fibre  strain  resulting  from  the  weight  only,  of  any 
member,  exceeds  ten  per  cent,  of  the  allowed  unit  strain  on 
such  member,  such  excess  must  be  considered  in  propor- 
tioning the  areas. 

42.  Plate  girders  shall  be  proportioned  upon  the  suppo- 
sition that  the  bending  or  chord  strains  are  resisted  entirely 
by  the  upper  and  lower  flanges,  and  that  the  shearing  or 
web  strains  are  resisted  entirely  by  the  web-plate ;  no  part 
of  the  web-plate  shall  be  estimated  as  flange  area. 

The  distance  between  centres  of  gravity  of  the  flange 
areas  will  be  considered  as  the  effective  depth  of  all  girders. 

43.  The  webs   of   plate  girders  must  be  stiffened  at  in- 
tervals, about  the  depth  of  the  girders,  wherever  the  shear- 
ing strain  per  square  inch  exceeds  the  strain  allowed  by  the 
following  formula : 

12  OOO 

Allowed  shearing  strain  =      ' 


i  +     3,000 

where  H  =  ratio  of  depth  of  web  to  its  thickness;  but  no 
web-plates  shall  be  less  than  three-eighths  of  inch  in  thick- 
ness. 

44.  Rolled  beams  shall  be  proportioned  (§§  30,  35)  by  their 
moments  of  inertia. 

45.  The     areas    of    counter   rods    shall    be    determined 
by  taking  the  difference  in  areas  due  to  the  live  and  dead 
load  strains  considered  separately  (§  30);  the  counter  rods 
in  any  one  panel  must  have  a  combined  sectional  area  of  at 
least  three  square  inches,  or  else  must  be  capable  of  carry- 
ing all  the  counter  live  load  in  that  panel. 


11 


DETAILS  OF   CONSTRUCTION. 

46.  All  the  connections  and  details  of  the  several  parts  of  Details, 
the  structures  shall  be  of  such  strength  that,  upon  testing, 
ruptures  shall  occur  in  the  body  of  the  members  rather  than 

in  any  of  their  details  or  connections. 

47.  Preference  will  be  had  for  such  details  as  shall  be 
most  accessible  for  inspection,  cleaning  and  painting ;  no 
closed  sections  will  be  allowed. 

48.  The  webs  of  plate  girders  must  be  spliced  at  all  joints  webspiices. 
by  a 'plate  on  each  side  of  the  web. 

49.  All   web-plates   must   have    stiffeners   over    bearing  stiffeners. 
points  and  at  points  of  local  concentrated  loadings. 

50.  The  pitch  of  rivets  in  all  classes  of  work  shall  never  Riveting, 
exceed  6  inches,  or  sixteen  times  the  thinnest  outside  plate, 

nor  be  less  than  three  diameters  of  the  rivet. 

51.  The  rivets  used  shall  generally  be  £  and  |  inch  dia- 
meter. 

52.  The  distance  between  the  edge  of  any  piece  and  the 
centre  of  a  rivet-hole  must  never  be  less  than    i£  inches, 
except  for  bars  less  than  2\  inches  wide;  when  practicable 
it  shall  be  at  least  two  diameters  of  the  rivet. 

53.  In  punching  plate  or  other  iron,  the  diameter  of  the 
die  shall  in  no  case  exceed  the  diameter  of  the  punch  by 
more  than  T\  of  an  inch,  and  all  holes  must  be  clean  cuts 
without  torn  or  ragged  edges. 

54.  All   rivet-holes   must  be   so   accurately   spaced   and 
punched  that  when  the  several  parts  forming  one  member 
are  assembled  together,  a  rivet  TV  inch  less  in  diameter  than 
the  hole  can  generally  be  entered,  hot,  into  any  hole,  with- 
out reaming  or  straining  the  iron  by  "  drifts ;"  occasional 
variations  must  be  corrected  by  reaming. 

55.  The  rivets  when   driven   must  completely   fill  the 
holes.     The  rivet-heads  must  be  round  and  of  a  uniform  size 
for  the  same  sized  rivets  throughout  the  work.     They  must 
be  full  and  neatly  made,  and  be  concentric  to  the  rivet-hole, 
and  thoroughly  pinch  the  connected  pieces  together. 

56.  Wherever  possible,  all  rivets  must  be  machine  driven. 
The  machines  must  be  capable  of  retaining  the  applied  pres- 


12 


Bolts. 


Splices. 


sure  after  the   upsetting  is  completed.     No   hand-driven 
rivets  exceeding  |  inch  diameter  will  be  allowed. 

57.  Field  riveting   must   be   reduced   to  a  minimum  or 
entirely  avoided,  where  possible. 

58.  The  effective  diameter  of  a  driven  rivet  will  be  as- 
sumed the  same  as  its  diameter  before  driving.     In  deduct- 
ing the  rivet-holes  to  obtain  net  sections  in  tension  mem- 
bers, the  diameter  of  the  rivet-hole  will  be  assumed  as  -J- 
inch  larger  than  the  undriven  rivets. 

59.  When  members  are  connected  by  bolts  which  trans- 
mit shearing  strains,  the  holes  must  be  reamed  parallel  and 
the  bolts  turned  to  a  driving  fit. 

60.  The  several  pieces  forming  one  built  member  must  fit 
closely  together,  and  when  riveted  shall  be  free  from  twists, 
bends  or  open  joints. 

61.  All  joints  in  riveted  tension  members  must  be  fully 
and  symmetrically  spliced. 

Abutting  joints,  fo  jn  compression  members,  abutting  joints  with  planed 
faces  must  be  sufficiently  spliced  to  maintain  the  parts  ac- 
curately in  contact  against  all  tendencies  to  displacement. 

63.  In   compression   members,  abutting  joints   with   un- 
tooled   faces  must  be  fully  spliced,  as  no  reliance  will  be 
placed  on  such  abutting  joints.     The  abutting  ends  must, 
however,  be  dressed  straight  and  true,  so  there  will  be  no 
open  joints. 

64.  All  the  angles,  filling  and  splice  plates  on  the  webs  of 
girders  and  riveted  members  must  fit  at  their  ends  to  the 
flange  angles,  sufficiently  close  to  be  sealed  when  painted, 
against  admission  of  water;  but  need  not  be  tool  finished. 

web piates.  65.  Web-plates  of  all  girders  must  be  arranged  so  as  not 
to  project  beyond  the  faces  of  the  flange  angles,  nor  on  the 
top  be  more  than  T^  inch  below  the  face  of  these  angles,  at 
any  point. 

66.  Wherever  there  is  a  tendency  for  water  to  collect, 
the  spaces  must  be  filled  with  a  suitable  waterproof  material. 

nange  piates.  67.  In  girders  with  flange  plates,  at  least  one-half  of  the 
flange  section  shall  be  angles  or  else  the  largest  sized  angles 
must  be  used. 


13 

68.  In  lattice  girders,  the  web  members  must  be  double 
and  connect  symmetrically  to  the  web  of  the  flanges. 

69.  The  compression  flanges  of  beams  and  girders  shall  be 
stayed  against  transverse  crippling  when  their  length  is  more 
than  thirty  times  their  width. 

70.  The  unsupported  width  of  plates  subjected  to  com- 
pression shall  not  exceed  thirty  times  their  thickness  ;  except 
cover  plates  of  top  chords  and  end   posts,   which  will  be 
limited  to  forty  times  their  thickness. 

71.  The  flange  plates  of  all  girders  must  be   limited  in 
width  so  as  not  to  extend  beyond  the  outer  lines  of  rivets 
connecting  them  with  the  angles,  more  than  five  inches  or 
more  than  eight  times  the  thickness  of  the  first  plate.  Where 
two  or  more  plates  are  used  on  the  flanges,  they  shall  either 
be  of  equal  thickness  or  shall  decrease  in  thickness  outward 
from  the  angles. 

72.  No  iron  shall  be  used  less  than  £  inch  thick,  except 
for  lining  or  filling  vacant  spaces. 

73.  The  heads  of  eye-bars  shall  be  so  proportioned  and  Eye  Bar8' 
made,  that  the  bars  will  preferably  break  in  the  body  of 

the  original  bar  rather  than  at  any  part  of  the  head  or  neck. 
The  form  of  the  head  and  the  mode  of  manufacture  shall  be 
subject  to  the  approval  of  the  Engineer  of  the  Railroad 
Company.  The  heads  must  be  formed  either  by  the 
process  of  upsetting  and  forging,  or  by  the  process  of 
upsetting,  piling  and  forging.  No  welding  will  be  allowed 
in  the  body  of  the  bars,  nor  in  the  process  of  piling,  welding 
seams  in  any  other  direction  than  parallel  to  the  sides  of 
the  original  bars. 

74.  The  bars  must  be  free  from  flaws  and  of  full  thick- 
ness in  the  necks.     They  shall  be  perfectly  straight  before 
boring.     The  holes  shall  be  in  the  centre  of  the  head,  and 
on  the  centre  line  of  the  bar. 

75.  The  bars  must  be  bored  to  lengths  not  varying  from 
the  calculated  lengths  more  than  ^  of  an  inch  for  each  25 
feet  of  total  length. 

76.  Bars  which   are   to  be   placed  side   by  side  in  the 
structure  shall  be  bored  at  the  same  temperature  and  of 
such  equal  length  that  upon  being  piled  on  each  other  the 

*& 

OF  THE 

UNIVERSITY 


u 

pins  shall  pass  through  the   holes   at   both    ends  without 
driving. 

77.  The   lower   chord    shall    be    packed    as   narrow    as 
possible. 

78.  The  pins  shall  be  turned  straight  and  smooth,  and 
shall  fit  the  pin-holes  within  ^0  of  an  inch,  for  pins  less  than 
4^  inches  diameter ;  for  pins  of  a  larger  diameter  the  clear- 
ance may  be  -fa  inch. 

79.  The  diameter  of  the  pin  shall  not  be  less  than  two- 
thirds  the  largest  dimension  of  any  tension   member   at- 
tached to   it.     The  several  members  attaching  to  the  pin 
shall  be  so  packed  as  to  produce  the  least  bending  moment 
upon   the   pin,  and   all  vacant   spaces  must  be  filled  with 
wrought-iron  filling  rings. 

80.  All  rods  and  hangers  with  screw  ends  shall  be  upset 
at    the   ends,  so   that  the  diameter  at  the  bottom  of    the 
threads  shall  be  y1^  inch  larger  than  any  part  of  the  body  of 
the  bar. 

81.  All  threads  must  be  of  the  United  States  standard, 
except  at  the  ends  of  the  pins. 

82.  Floor  beam  hangers  shall  be  so  placed  that  they  can 
be  readily  examined  at  all  times.     When  fitted  with  screw 
ends  they  shall  be  provided  with  check  nuts.     Preference 
will  be  given  to  hangers  without  screw  ends. 

83.  When  bent  loops  are  used,  they  must  fit  perfectly 
around  the  pin  throughout  its  semi-circumference. 

84.  All  nuts  on  floor  beam  hangers  and  counter  rods  must 
have  the  bearing  faces  faced  square  to  the  axes  of  the  screw 
ends. 

85.  Compression  members  shall  be  of  wrought-iron,  and 
of  approved  forms. 

86.  The  pitch  of  rivets  at  the  ends  of  compression  mem- 
bers shall  not  exceed  four  diameters  of  the    rivets  for  a 
length  equal  to  twice  the  width  of  the  member. 

87.  The  open  sides  of  all  compression  members  shall  be 
stayed  by  batten  plates  at  the  ends  and  diagonal  lattice- 
work at  intermediate  points.     The  batten  plates  must  be 
placed  as  near  the  ends  as  practicable,  and  shall  have  a 
length  of  ij  times  the  width  of  the  member.     The  size  and 


15 

spacing  of  the  lattice  bars  shall  be  duly  proportioned  to 
the  size  of  the  member.  They  must  not  be  less  than  2  X  i 
inches  for  posts  6  inches  wide,  nor  4X1  inches  for  posts  15 
inches  wide.  They  shall  be  inclined  at  an  angle  not  less  than 
60°  to  the  axis  of  the  member.  The  pitch  of  the  latticing 
must  not  exceed  the  width  of  the  channel  plus  nine  inches. 

88.  Where   necessary,  pin-holes    shall    be  reinforced  by 
plates,  so  the  allowed  pressure  on   the  pins  shall  not  be 
exceeded.     These  reinforcing  plates  must  contain  enough 
rivets  to  transfer  their  proportion  of  the  bearing  pressure, 
and  at  least  one  plate  on  each  side  shall  extend  not  less  than 
six  inches  beyond  the  edge  of  the  batten  plates.     (§  87.) 

89.  Where  the  ends  of  compression  members  are  forked 
to  connect  to  the  pins,  the  aggregate  compressive  strength 
of  these  forked  ends  must  equal  the  compressive  strength 
of  the  body  of  the  members ;  in  order  to  insure  this  result 
the  aggregate  sectional  area  of  the  forked  ends,  at  any  point 
between  the  inside  edge  of  the  pin-hole  and  six  inches  be- 
yond the  edge  of  the  batten  plate,  shall  be  about  double 
that  of  the  body  of  the  member. 

90.  In  compression  chord  sections,  the  material  must  mostly 
be  concentrated  at  the  sides,  in  the  angles  and  vertical  webs. 
Not  more  than  one  plate,  and  this  not  exceeding  £  inch  in 
thickness,  shall  be  used  as  a  cover  plate,  except  when  neces- 
sary to  resist  bending  strains.     (§  41.) 

91.  The   sections   of  compression   chords  shall   be  con-TopOhord 
nected  at  the  abutting  ends  by  splices  sufficient  to  hold  them  Sp 
truly  in  position. 

92.  The  ends  of  all  square-ended  members  shall  be  planed 
smooth,  and  exactly  square  to  the  centre  line  of  strain. 

93.  All  members  must  be  free  from  twists  or  bends.     Por- 
tions exposed  to  view  shall  be  neatly  finished. 

94.  Pin-holes  shall  be  bored  exactly  perpendicular  to  a 
vertical  plane  passing  through  the  centre  line  of  each  mem- 
ber, when  placed  in  a  position  similar  to  that  it  is  to  occupy 
in  the  finished  structure. 

95.  Abutting  joints  in  truss  bridges  shall  be  in  exact  con- Abutting  joints, 
tact  throughout. 


16 


Transverse 

Diagonal 

Braciug. 


Lateral  Bracing.  96.  In  no  case  shall  any  lateral  or  diagonal  rod  have  a  less 
area  than  J  of  a  square  inch. 

97.  The  attachment  of  the  lateral  system  to  the  chords 
shall  be  thoroughly  efficient.     If  connected  to  suspended 
floor  beams,  the  latter  shall  be  stayed  against  all  motion. 

98.  Preference  will  be  given  for  a  stiff  angle  iron  lateral 
system  between  the  chords  on  the  level  of  the  floor. 

99.  All   through  bridges  with  top  lateral    bracing  shall 
have  wrought-iron  latticed  portals,  of  approved  design,  at 
each  end  of  the  span,  connected  rigidly  to  the  end  posts. 
They  shall  be  as  deep  as  the  specified  head-room  will  allow. 

(§  38.) 

100.  When  the  height  of  the  trusses  exceed  25  feet,  an 
approved  system  of  overhead  diagonal  bracings  shall  be  at- 
tached to  each  post  and  to  the  top  lateral  struts. 

101.  Pony  trusses  and  through  plate  or  lattice  girders 
shall  be  stayed  by  knee  braces  or  gusset  plates  attached  to 
the  top  chords  at  the  ends,  and  at  intermediate  points,  not 
more  than  10  feet  or  a  panel  length  apart,  and  attached 
below  to  the  cross  floor  beams  or  to  the  transverse  struts. 

102.  All  deck  girders  shall  have  transverse  braces  at  the 
end.     All  deck  bridges  shall  have  transverse  bracing  at  each 
panel  point.     This  bracing  shall  be  proportioned  to  resist 
the  unequal  loading  of  the  trusses.     The  transverse  bracing 
at  the  ends  shall  be  of  the  same  equivalent  strength  as  the 
end  top  lateral  bracing. 

103.  All  bed-plates  must  be  of  such  dimensions  that  the 
greatest  pressure  upon  the  masonry  shall  not  exceed  250 
pounds  per  square  inch. 

Friction  Boilers  104.  All  bridges  over  75  feet  span  shall  have  at  one  end 
nests  of  turned  friction  rollers,  formed  of  wrought-iron  or 
steel,  running  between  planed  surfaces.  The  rollers  shall 
not  be  less  than  2  inches  diameter,  and  shall  be  so  pro- 
portioned that  the  pressure  per  lineal  inch  of  rollers  shall 
not  exceed  the  product  of  the  square  root  of  the  diameter 
of  the  roller  in  inches  multiplied  by  500  pounds,  ($oo\/  d.)- 

105.  Bridges  less  than  75  feet  span  shall  be  secured  at  one 
end  to  the  masonry,  and  the  other  end  shall  be  free  to  move 
upon  planed  surfaces. 


Bed  Plates. 


17 

106.  Where  two   spans  rest  upon  the  same  masonry,  a 
continuous  wrought-iron  plate,  not  less  than  f-inch  thick, 
shall  extend  under  the  two  adjacent  bearings. 

107.  All  the  bed-plates  and  bearings  under  fixed  and  mov- 
able ends  must  be  fox-bolted  to  the  masonry ;  for  trusses, 
these  bolts  must  not  be  less  than  ij  inches  diameter;  for 
plate    and   other  girders,   not  less  than    |-inch   diameter. 
The  contractor  must  furnish  all  bolts,  drill  all  holes,  and  set 
bolts  to  place  with  sulphur. 

108.  While  the  roller  ends  of  all  trusses  must  be  free  to 
move   longitudinally   under  changes  of  temperature,  they 
shall  be  anchored  against  lifting  or  moving  sideways. 

109.  All  iron  bridges  with  parallel  chords  shall  be  given  a°amber- 
camber  by  making  the  panel  lengths  of  the  top  chord  longer 
than  those  of  the  bottom  chord,  in  the  proportion  of  -J  of  an 
inch  to  every  ten  feet. 

no.  All  bolts  must  be  of  neat  lengths,  and  shall  have  aBoits. 
washer  under  the  heads  and  nuts  where  in  contact   with 
wood. 

in.  The  lower  struts  in  trestle  towers  shall  be  securely 
anchored  to  intermediate  masonry  piers  when  the  magnitude 
of  the  structure,  in  the  opinion  of  the  Engineer,  requires  it ; 
these  struts  shall  always  have  ample  stiffness  to  move  the 
tower  columns  under  the  effects  of  changes  of  temperature, 
and  prevent  the  slacking  of  the  diagonal  brace  rods. 

112.  Tower  footings  and  bed-plates  must  be  planed  on  all  Bed  piate 
sliding  surfaces ;  and  the  holes  for  anchor  bolts  slotted  to 
allow  for  the  proper  amount  of  movement.  (§  27.) 

113.  All  joints  in  the  tower  columns  shall  be  fully  spliced 
for  all  possible  tension  strains,  and  to  hold  the  parts  firmly  in 
position. 

114.  The  connection  of  all  the  diagonal  tension  members 
with  the  columns  shall,  preferably,  be  made  by  means  of  pins 
passing  through  the  column's  axis. 

115.  The  tension  diagonals  shall  be  adjustable,  but  must 
have  check  nuts  at  all  adjustable  points ;  and  shall  be  sup- 
ported and  clamped  at  suitable  intervals  to  prevent  sagging 
and  rattling. 


18 

workmanship.  Il6  ^]]  workmanship  shall  be  first-class  in  every  par- 
ticular. 

1 17.  Whenever  necessary  for  the  protection  of  the  thread, 
provision  shall  be  made  for  the  use  of  pilot  nuts  in  erection. 

USE  OF  STEEL. 

Medium steei.  jjg.  Medium  steel  (§  139)  may  be  used  for  tension  mem- 
bers, plate  girders,  rolled  beams  and  top  chord  sections  with 
an  allowance  of  20  percent,  increase  above  allowed  working 
strains  on  wrought-iron  ;  and  for  all  posts  by  use  of  the  fol- 
lowing formulas,  in  place  of  those  given  for  wrought-iron 
(§33): 

p=  8,500 —  55 — for  live  load  strains. 

P=* 1 7,000—  i  io—  "   dead    " 
r 

p=i 3,000—  85—  "   wind    " 

Provided  that,  in  addition  to  the  previous  details  of  con- 
struction, 

1 19.  All  sheared  edges  of  plates  and  angles  be  planed  off 
to  a  depth  of  one-quarter  of  an  inch.     All  punched  holes  be 
reamed  to  a  diameter  of  |-inch  larger,  so  as  to  remove  all  the 
sheared  surface  of  the  metal. 

120.  No  sharp  or  unfilleted  re-entrant  corners  be  allowed. 

121.  All  rivets  to  be  of  steel. 

122.  Any  piece  which  has  been  partially  heated  or  bent 
cold,  be  afterwards  wholly  annealed. 

soft  steei.  I23-  Soft  steel  (§  141)  may  be  used  under  the  same  condi- 

tions as  wrought-iron  for  all  riveted  work. 

Provided,  that 

124.  Any  rivet  hole  punched,  as  in  ordinary  practice 
(§§  52  and  53),  will  stand  drifting  to  a  diameter  25  per  cent, 
greater  than  the  original  hole  without  cracking,  either  in  the 
periphery  of  the  hole  or  on  the  external  edges  of  the  piece, 
whether  they  be  sheared  or  rolled. 


ID 

QUALITY  OF   MATERIAL. 

IRON. 

125.  All  wrought-iron  must  be  tough,  fibrous  and  uniform Iron- 
in  character.     It  shall  have  a  limit  of  elasticity   of  not  less 
than  26,000  pounds  per  square  inch. 

Finished  bars  must  be  thoroughly  welded  during  the  roll- 
ing, and  be  free  from  injurious  seams,  blisters,  buckles,  cinder 
spots,  or  imperfect  edges  :  all  iron  for  eye-bars  or  other 
forgings  and  for  bent  plates,  must  be  capable  of  being  worked 
at  a  proper  heat  without  injury. 

126.  For  all  tension  members  high  test  bars  must  be  used,  Tension  Tests, 
capable  of  standing  the  following  tests  : 

127.  Full  sized  pieces  of  flat,  round  or  square  iron,  not 
over  4i  inches   in   sectional   area,   shall   have  an  ultimate 
strength  of  50,000  pounds  per  square  inch,  and  stretch  \2\ 
per  cent,  in  the  whole  length  of  the  body  of  the  bars. 

Bars  of  a  larger  sectional  area  than  4^  square  inches  will 
be  allowed  a  reduction  of  1,000  pounds  per  square  inch  for 
each  additional  square  inch  of  section,  down  to  a  minimum 
of  46,000  pounds  per  square  inch,  and  10  per  cent,  stretch 
in  the  whole  length  of  the  body  of  the  bars. 

128.  When  tested  in  specimens  of  uniform  sectional  area 
of  at  least  \  square  inch  for  a  distance   of  10  inches,  taken 
from  tension  members  which  have  been  rolled  to  a  section 
not  more  than  4^  square  inches,  the  iron  shall  show  an  ulti- 
mate strength  o(  52,000  pounds  per  square  inch,  and  stretch 
1 8  per  cent,  in  a  distance  of  8  inches. 

Specimens  taken  from  bars  of  a  larger  cross-section  than 
4^  inches  will  be  allowed  a  reduction  of  500  pounds  for  each 
additional  square  inch  of  section,  down  to  a  minimum  of 
48,000  pounds,  and  15  per  cent,  stretch. 

129.  The  same   sized  specimens   taken  from   angle    and 
other  shaped  iron  shall  have  an   ultimate  strength  of  48,000 
pounds   per   square  inch,  and   elongate    15   per  cent,  in   8 
inches. 

130.  The  same  sized  specimens  taken  from  plates  less  than 
24  inches  in  width,  shall  have  an  ultimate  strength  of  48,000 
pounds,  and  elongate  15  per  cent,  in  8  inches. 


20 

131.  The  same  sized  specimens  taken  from  plates  exceed- 
ing 24  inches  in  width,  shall  have  an  ultimate  strength  of 
46,000  pounds,  and  elongate  10  per  cent. 

Bending  Tests.  j-^.  All  iron  for  tension  members  must  bend  cold  for 
about  90  degrees,  to  a  curve  whose  diameter  is  not  over 
twice  the  thickness  of  the  piece,  without  cracking.  At  least 
one  sample  in  three  must  bend  180  degrees  to  this  curve 
without  cracking.  When  nicked  on  one  side,  and  bent  by 
a  blow  from  a  sledge,  the  fracture  must  be  nearly  all  fibrous, 
showing  but  few  crystalline  specks. 

133.  Specimens   from  angle,  plate  less  than  24  inches  in 
width  (130)  and  shaped  iron,  must  stand  bending  cold  through 
90  degrees,  and  to  a  curve  whose  diameter  is  not  over  three 
times  its  thickness,  without  cracking. 

Specimens  from  plates  wider  than  24  inches  must  stand 
bending  cold  through  90  degrees ;  and  to  a  curve  whose 
diameter  is  not  over  six  times  its  thickness,  without 
cracking. 

When  nicked  and  bent  the  fracture  must  be  mostly 
fibrous. 

134.  If  any  of  the  above  material  under  the  tests  shows  a 
decrease  of  stretch,  accompanied  by  an  increase  of  tensile 
strength,  amounting  to  500  pounds  per  square  inch  for  each 
one  per  cent,  change  of  stretch,  this  decrease  of  stretch  will 
not  be  cause  for  rejection,  if  the  material  still  satisfies  the 
bending  tests. 

135.  If  the  tests  of  the  tension  bars  (127  and  128)  show 
a  decrease  of  the  required  tensile  strength,   accompanied 
with  an  increase  of  stretch,  the  decrease  in  the  required 
tensile  strength  will  not  be  cause  for  rejection  if  the  tensile 
strength  does  not  fall  below  the  stated  minimum  require- 
ments, and  the  increase  of  stretch  amounts  to  an  additional 
per   cent,   for    each    500   pounds   decrease   in   the   tensile 
strength. 

Rivet  iron.  j^.  Rivets  shall  be  made  from  the  best  refined  iron,  and 

must  be  capable  of  being  bent  cold  until  the  sides  are  in 
close  contact  without  sign  of  fracture  on  the  convex  side. 


Of-     THE 

21  UNIVERSITY 

OF 

STEEL. 


137.  The   steel  must  be    uniform  in  character  for   each 
specified  kind.     The  finished  bars,  plates  and  shapes  must 
be  free  from  cracks  on  the  faces  or  corners,  and  have  a 
clean,  smooth  finish.     No  work  shall  be  put  upon  any  steel 
at  or  near  the  blue  temperature  or  between  that  of  boiling 
water  and  of  ignition  of  hard  wood  sawdust. 

138.  All  tests  shall  be  made  by  samples  cut  from  the  fin- 
ished  material  after  rolling.     The  samples  to  be  at  least 
12  inches  long,  and  to  have  a  uniform  sectional  area  not 
less  than  £  square  inch.     All  broken  samples  must  show 
uniform  fine  grained  fractures  of  a  blue  steel-gray  color, 
entirely  free  from  fiery  lustre  or  a  blackish  cast. 

139.  Medium  Steel  shall  have  an  ultimate  strength,  when  Medium  steei. 
tested  in  samples  of  the  dimensions  above  stated,  of  62,000 

to  68,000  pounds  per  square  inch,  an  elastic  limit  of  not-  less 
than  33,000  pounds  per  square  inch,  and  a  minimum  elonga- 
tion of  20  per  cent,  in  8  inches. 

140.  Before  or  after  heating  to  a  low  cherry  red  and  cool- 
ing in  water  at  82  degrees  Fah.,  this  steel  must  stand  bend- 
ing to  a  curve  whose  inner  radius  is  one  and  a  half  times 
the  thickness  of  the  sample,  without  cracking. 

141.  Soft  Steel  shall  have  an  ultimate  strength,  on  same  soft  steei. 
sized  samples,  of  54,000  to  62,000  pounds  per  square  inch, 

an  elastic  limit  not  less  than  30,000  pounds  per  square  inch, 
and  a  minimum  elongation  of  25  per  cent,  in  8  inches. 

142.  Before  or  after  heating  to  a  light  yellow  heat  and 
quenching  in  cold  water,  this  steel  must  stand  bending  180 
degrees,  to  a  curve  whose  inner  radius  is  equal  to  the  thick- 
ness of  the  sample,  without  sign  of  fracture. 

143.  All  rivets  will  be  made  of  soft  steel,  and  the  steel  for 
rivets  must,  under  the  above   bending  test,  stand   closing 
solidly  together  without  sign  of  fracture. 

CAST  IRON. 

144.  Except  where  chilled  iron   is  required,  all  castings  cast  iron. 
must  be  of  tough,  gray  iron,  free  from  cold  shuts  or  injur- 

ious blow  holes,  true  to  form  and  thickness,  and  of  a  work- 


manlike  finish.  Sample  pieces,  i  inch  square,  cast  from  the 
same  heat  of  metal  in  sand  moulds,  shall  be  capable  of  sus- 
taining, on  a  clear  span  of  4  feet  6  inches,  a  central  load  of 
500  pounds,  when  tested  in  the  rough  bar.  A  blow  from  a 
hammer  shall  produce  an  indentation  on  a  rectangular  edge 
of  the  casting  without  flaking  the  metal. 

TIMBER. 

Timber.  145.   The  timber   shall   be   strictly  first-class  white  pine, 

southern  yellow  pine  or  white  oak  bridge  timber ;  sawed 
true,  and  out  of  wind,  full  size,  free  from  wind  shakes,  large 
or  loose  knots,  decayed  or  sap  wood,  worm  holes,  or  other 
defects  impairing  its  strength  or  durability.  It  will  be  sub- 
ject to  the  inspection  and  acceptance  of  the  Engineer. 

INSPECTION. 

inspection.  146.  All   facilities   for  inspection   of    the   materials   and 

workmanship  shall  be  furnished  by  the  contractor.  He 
shall  furnish  without  charge  such  specimens  (prepared)  of 
the  several  kinds  of  iron  or  steel  to  be  used,  as  may  be  re- 
quired to  determine  their  character. 

147.  The   contractor  must  furnish  the   use  of  a   testing 
machine  capable  of  testing  the  above  specimens  at  all  mills 
where  the  iron  or  steel  may  be  manufactured,  free  of  cost. 

148.  Full  sized  parts  of  the  structure  may  be  tested  at 
the  option  of  the  Engineer  of  the  Railroad  Company,  but 
if  tested  to  destruction,  such  material  shall  be  paid  for  at 
cost,  less  its  scrap  value  to  the  contractor,  if  it  proves  sat- 
isfactory.    If  it  does  not  stand  the  specified  tests,  it  will  be 
considered  rejected  material,  and  be  solely  at  the  cost  of  the 
contractor. 

PAINTING. 

149.  All  iron  work  before  leaving  the  shop  shall  be  thor- 
oughly cleaned  from  all  loose  scale  and  rust,  and  be  given 
one  good  coating  of  pure  raw  linseed  oil,  well  worked  into 
all  joints  and  open  spaces. 


23 

150.  In  riveted  work  the  surfaces  coming  in  contact  shall 
each  be  painted  before  being  riveted  together.     Bottoms  of 
bed-plates,  bearing-plates,  and  any  parts  which  are  not  ac- 
cessible for  painting  after  erection,  shall  have  two  coats  of 
paint ;  the  paint  shall  be  a  good  quality  of  iron  ore  paint, 
subject  to  approval  of  the  Engineer. 

151.  After  the  structure  is  erected,  the  iron  work  shall  be 
thoroughly  and  evenly  painted  with  two  additional  coats  of 
paint,  mixed  with  pure  linseed  oil,  of  such  color  as  may  be 
directed.     All  recesses  which  will  retain  water,  or  through 
which  water  can  enter,  must  be  filled  with  thick  paint  or 
some  water-proof  cement  before  receiving  the  final  painting. 

152.  Pins,  bored  pin-holes  and  turned  friction  rollers  shall 
be  coated  with  white  lead  and  tallow  before  being  shipped 
from  the  shop. 

ERECTION. 

153.  The  contractor  shall  furnish  all   staging   and   false  Erection, 
work,  shall  erect  and  adjust  all  the  iron  work,  and  put  in 
place  all  floor  timbers,  guards,  etc.,  complete,  ready  for  the 
rails. 

154.  The  contractor  shall  so  conduct  all  his  operations  as 
not  to  impede  the  operations  of  the  road,  interfere  with  the 
work  of  other  contractors,  or  close  any  thoroughfare  by  land 
or  water. 

155.  The  contractor  shall  assume  all  risks  of  accidents  to 
men  or  material  prior  to  the  acceptance  of  the  finished  struc- 
ture by  the  Railroad  Company. 

The  contractor  must  also  remove  all  false  work,  piling  and 
other  obstructions,  or  unsightly  material  produced  by  his 
operations. 

FINAL  TEST. 

156.  Before  the  final  acceptance  the  Engineer  may  make  Final  Test. 
a  thorough  test  by  passing  over  each  structure  the  specified 
loads,  or  their  equivalent,  at  a  speed  not  exceeding  45  miles 

an  hour,  and  bringing  them  to  a  stop  at  any  point  by  means 
of  the  air  or  other  brakes,  or  by  resting  the  maximum  load 
upon  the  structure  for  twelve  hours. 


24: 

After  such  tests  the  structures  must  return  to  their  origi- 
nal positions  without  showing  any  permanent  change  in  any 
of  their  parts. 

SUPPLEMENTARY. 

The  following  special  clauses  shall  apply  in  addition  to 
previous  general  clauses,  to  the  special  work  included  in  the 
attached  contract: 


25 


Proposals  for  building  and  erecting  complete,  ready  for 

the ,  a  bridge  over 

near 

on  the Division, 

Railroad,  in  accordance  with 

the  attached  specifications  and  accompanying  profile,  will  be 
received  up  to The  live 

load  to  be  adopted  for  this  bridge  will  be  Class 

paragraph  23. 


"The  most  perfect  system  of  rules  to  insure  success  must 
be  interpreted  upon  the  broad  grounds  of  professional  intelli- 
gence and  common  sense." 


GENERAL  SPECIFICATIONS 

STEEL  HIGHWAY  AND  ELECTRIC  RAILWAY 
BRIDGES  AND  VIADUCTS. 


NEW    AND     REVISED     EDITION, 
19O1 


By   THEODORE   COOPER, 

Consulting  En.. 


SAt 


By  THEODORE  COOPER,  M.  Am,  Soc.  0.  E. 

Specifications  for  Steel  Railroad  Bridges,  1901,   .        .     SO  50 

u              n                 "             "    previous  editions  25 

«               "           Highway  Bridges,  1901,   .  t>0 

tt              it                  «             <c    previous  editions  25 
American    Railroad    Bridges    (reprint   from  Transac- 
tions  of   American    Society    of    Civil    Engineers, 

July,  1889),  60  pages,  8vo,  cloth,      .                       •  2  UU 


FOR  SALE  BY 


ENGINEERING  NEWS  PUBLISHING  COMPANY, 

22O  Broadway,  New  York. 


Copyright  by  THEODORE  COOPER 

Consulting  Engineer,  35  Broadway,  New  York. 


General  Specifications  for  Steel  Highway 

and  Elecjric  Railway  Bridges 

and  Viaducts, 


FIFTH  EDITION. 
1901_ 


GENERAL  DESCRIPTION. 

Bridges  under  these  specifications  are  divided  into  six  classes. 
classes,  for  different  localities  and  various  loadings,  as  fol- 
lows: (§38.) 

Class  Ai.  City  bridges  having  buckle-plate  floors  and  an 
accepted  form  of  paving  resting  on  a  concrete  base.  (§  29.) 

Class  A2.  City  bridges  having  plank  flooring.     (§  29.) 

Class  B.  Suburban  bridges  or  Interurban  bridges  carry- 
ing heavy  electric  cars.  (§  29.) 

Class  C.  Town  or  country  bridges  carrying  light  elec- 
tric cars  or  bridges  carrying  heavy  loads  from  quarries  or 
manufactories. 

Class  D.  Country  bridges  carrying  only  ordinary  high- 
way traffic. 


Class  Ei.  Bridges  carrying  heaviest  motor  cars,  only. 
Class  E2.  Bridges  carrying  light  motor  cars,  only. 


i.  All  parts  of  the  structures  shall  be  of  wrought  steel, 
except  the  flooring,  floor  joists  and  wheel  guards,  when 
wooden  floors  are  used.  Cast-iron  or  cast-steel  may  be 
used  in  the  machinery  of  movable  bridges,  for  wheel 
guards,  and  in  special  cases  for  bed-plates. 

Kind  of  Girders.  2.  The  following  kinds  of  girders  shall  preferably  be 
employed  : 

Spans,  up  to    25  feet Rolled  beams. 

"       20  to    40    "    Rolled  beams  or  plate  girders. 

"       40  to    80    "    Riveted  plate  or  lattice  girders. 

"       80  to  1 20    "    Lattice  girders. 

"       over   120    "    Lattice  or  pin-connected  trusses. 

Length  of  span.  In  calculating  strains  the  length  of  span  shall  be  under- 
stood to  be  the  -distance  between  centres  of  end  pins  for 
trusses,  c.  to  c.  of  trusses  for  cross  floor  beams,  and  be- 
tween centres  of  bearing  plates  for  all  longitudinal  beams 
and  girders. 

T?u™es[  3-  Unless  otherwise  specified,  the  form  of  bridge  trusses 
may  be  selected  by  the  bidder ;  for  through  bridges,  the 
end  vertical  suspenders  and  two  panels  of  the  lower  chord, 
at  each  end,  will  be  made  rigid  members.  In  through 
bridges,  the  floor  beams  shall  be  riveted  to  the  posts,  above 
or  below  the  pins. 

Lateral  Bracing.  4-  All  lateral,  sway  and  portal  bracing  must  be  made  of 
shapes  capable  of  resisting  compression  as  well  as  tension, 
and  must  have  riveted  connections.  All  bridges  must  have 
lateral  struts  at  the  ends,  except  where  end  floor  beams  act 
as  such. 

Trestle  Towers.  5.  Each  trestle  bent  shall,  as  a  general  rule,  be  composed 
of  two  supporting  columns,  and  the  bents  united  in  pairs  to 
form  towers;  each  tower  thus  formed  of  four  columns  shall 
be  thoroughly  braced  in  both  directions,  and  have  struts 
between  the  feet  of  the  columns.  The  feet  of  the  columns 


must   be   secured    to   an    anchorage   capable   of   resisting 
double  the  specified  wind  forces.     (§  40.) 

6.  Each  tower  shall  have  sufficient  base,  longitudinally, 
to  be  stable   when  standing  alone,  without  other  support 
than  its  anchorage.     (§§  40,  43.) 

7.  Tower  spans  for  high  trestles  shall  not  be  less  than  30 
feet. 

8.  Where  footwalks  are  required,  they  will  generally  be  Foot-walks. 
placed  outside  of  the  trusses  and  supported  on  longitudinal 
beams  resting  on  overhanging  steel  brackets. 

9.  A  strong  and  suitable  handrailing  will   be  placed  at  Railing, 
each  side  of  the  bridge  and  be  rigidly  attached  to  the  su- 
perstructure. 

10.  For  all  through  bridges  there  shall  be  a  clear  head- Head-room, 
room  of  15  feet  above  the  floor,  for  Classes  A,  B,  C  and  E ; 

and  a  minimum  head-room  of  I2J^  feet  for  Class  D. 

11.  In  comparing  different  proposals,  the  relative  cost  of  Proposals, 
the  required  masonry  or  changes  in  existing  work  will  be 
taken  into  consideration. 

12.  Contractors   in   submitting   proposals   shall    furnish 
complete    strain    sheets,   general    plans   of    the   proposed 
structures,  and  such  detail  drawings  as  will  clearly  show 
the  dimensions  of  all  the  parts,  modes  of  construction  and 
the  sectional  areas. 

13.  Upon  the  acceptance  of  the  proposal  and  the  execu- 
tion of  contract,  all  working  drawings  required  by  the  En- 
gineer must  be  furnished  free  of  cost. 

14.  No  work  shall  be  commenced  or  materials  ordered  Approval  of 
until  the  working  drawings  are  approved  by  the  Engineer 

in  writing;  if  such  working  drawings  are  detained  more 
than  one  week  for  examination,  the  Contractor  will  be 
allowed  an  equivalent  extension  of  time. 

FLOOR   SYSTEM. 

15.  All  cross  floor  beams  will  be  rolled  or  riveted  steel  Floor  Girders, 
girders,   rigidly   connected    to   the   trusses    at    the    panel 
points. 

16.  All  longitudinal  girders  of  bridges  of  Classes  Ai  and 


Aa  will  be  of  steel;  all  track  stringers  of  bridges  of  Classes 
B,  C  and  E  will  be  of  steel.  Unless  otherwise  specified  all 
other  longitudinal  girders  of  Classes  B  and  C  will  be  of 
steel.  The  longitudinal  girders  of  bridges  of  Class  D  may 
be  either  of  wood  or  steel.  When  the  longitudinal  beams 
are  of  steel,  they  must  be  securely  fastened  to  the  cross 
floor  beams. 

COUNTRY  BRIDGES. 

Floor,  i/.  Wooden  floor  joists  will  be  spaced  not  over  2  feet 
centres,  and  will  lap  by  each  other,  so  as  to  have  a  full 
bearing  on  the  floor  beams,  and  will  be  separated  \  inch  for 
/  free  circulation  of  air.  Their  scantling  will  vary  in  ac- 
cordance with  the  length  of  panels  selected,  but  shall  never 
be  less  than  3  inches,  or  one-fourth  of  depth  in  width. 
When  spaced  not  over  2-foot  centres,  one  joist  shall  be 
considered  as  carrying  only  two-thirds  of  the  concentrated 
live  load. 

1 8.  The  floor  plank  shall  be inches  thick,  laid  with 

|-inch  openings,  and  spiked  to  each  supporting  joist. 
When  this  is  to  be  covered  with  an  additional  wearing 
floor  (§  19),  it  must  be  laid  diagonally  and  with  -J  inch 
openings ;  all  plank  shall  be  laid  with  the  heart  side 
down.  The  floor  plank  must  have  a  thickness,  in  inches, 
at  least  equal  to  the  distance  apart  of  these  beams,  in  feet, 
with  a  minimum  thickness  of  2\  inches.  The  floor  plank 
must  bear  firmly  upon  the  beams  and  be  securely  fastened 
to  the  same. 

79.  Where  specified  an  additional  wearing  floor  \\  inches 
thick  of  white  oak  plank  shall  be  placed  over  the  above. 
(§  i«.) 

20.  The  footwalk  plank  will  be  2  inches  thick  and  not 
over  6  inches  wide,  spaced  with  J  inch  openings. 

21.  There  will  be  a  wheel  guard,  of  a  scantling  not  less 
than  6x4,  on  each  side  of  the  roadway  to  prevent  the  hubs 
of  wheels  striking  any  part  of  the  bridge.     It  should   be 

^blocked  up  from  the  floor  to  admit  drainage  and  ventilation. 

strain      22.  The  maximum  strain  allowed  upon  the  extreme  fibre 
of  the  joist  will  be  1,200  pounds  per  square  inch  on  yellow 


pine  and  white  oak,  and   1,000  pounds  per  square  inch  on 
white  pine  and  spruce. 

CITY  BRIDGES. 

23.  Buckle  plates  will  be  not  less  than  T5^  inch  thick  and  Buckle  piates. 
will  crown  2  inches  at  the  centre.     Plates  of  this  thickness 

and  crown  may  be  used  to  widths  of  4  feet  under  the  road- 
way and  5  feet  under  the  footwalks.     (§§  93-96.) 

24.  Bridges  with  buckle  plate  floors  will  have  a  suitable 
metal  curb  on  each  side  of  the  roadway  to  hold  paving  and 
act  as  a  wheel  guard.     The  wheel  guard  must  be  so  ar- 
ranged that  it  can  be  removed  and  replaced  when  worn  or 
injured.     There  will  also  be  a  metal  edging  strip  on  each 
side  of  the  footwalks  to  hold  the  paving  in  place. 

25.  The  concrete  over  buckle-plates  shall  beat  least  3 concrete, 
inches  thick  on  the  roadway  and  2  inches  thick  on  the  side- 
walks, over  the  highest  point  to  be  covered,  not  counting 
rivet  heads. 

26.  The  sidewalks  shall  slope  i  inch  in  5  feet,  preferably 
towards  the  roadway.     The  roadway  shall  crown  from  curb 
to  centre  i  inch  for  each    10  feet  of  the  roadway   width. 
The  depth  of  the  curb  will  be  6  inches. 

27.  The  subgrade,  top  of  concrete,  for  the  sidewalks  will 
be inches  below  final  grade  and  slope. 

The  concrete  over  roadway  will  be  laid  to  the  correct 

crowning  and  elevation  to  allow inches  for  the  selected 

paving. 

28.  Scuppers  must  be  provided  at  frequent  intervals  along  Scuppers. 
the   curbs   or  wheel  guards  for  drainage  and  for  passing 

the  sweepings  and  snow,  clear  from  contact  with  any  parts 
of  the  tracks  or  floor  system. 

29.  Classes  A  and  B  shall  be  designed  to  carry  at  any  Double  Track, 
future  time  a  double-track  electric  railway. 

ELECTRIC  RAILWAY  BRIDGES. 

30.  The  wooden  floors  will  consist  of  transverse  ties  or  wooden  Floor. 
floor  timbers;  their  scantling  will  vary  in  accordance  with 


6 

the  design  of  the  supporting  steel  floor.  (§  22.)  They  shall 
be  spaced  with  openings  not  exceeding  six  inches,  and  shall 
be  notched  down  J^  inch  and  be  secured  to  the  supporting 
girders  by  f -inch  bolts  at  distances  not  over  six  feet  apart. 
For  deck  bridges  the  ties  will  extend  the  full  width  of  the 
bridge,  and  for  through  bridges  at  least  every  other  tie 
shall  extend  the  full  width  of  bridge  fora  footwalk. 
Guard  Timbers.  31.  There  shall  be  a  guard  timber  (scantling  not  less  than 
5  x/f)  on  each  side  of  each  track,  with  its  inner  face  parallel 

to  and  at feet inches  from  centre  of  track.    Guard 

timbers  must  be  notched  one  inch  over  every  floor  timber, 
and  be  spliced  over  a  floor  timber  with  a  half-and-half  joint 
of  six  inches  lap.  Each  guard  timber  shall  be  fastened  to 
every  third  floor  timber  and  at  each  splice  with  a  three- 
quarter  (|)  inch  bolt.  All  heads  or  nuts  on  upper  faces  of 
ties  or  guards  must  be  countersunk  below  the  surface  of 
the  wood.  (§  76.) 

32.  The  guard  and  floor  timbers  must  be  continuous  over 
all  piers  and  abutments. 

33.  The  floor  timbers  from  centre  to  each  end  of  span 
must  be  notched  down  over  the  longitudinal  girders  so  as  to 
reduce  the  camber  in  the  track,  as  directed  by  the  Engineer. 

34.  All  the  floor  timbers  shall  have  a  full  and  even  bearing 
upon  the  stringers ;  no  open  joints  or  shims  will  be  allowed. 

35.  On  curves  the  outer  rail  must  be  elevated,  as  may  be 
directed  by  the  Engineer. 

idth.  36.  In  all  through  bridges  the  clear  width  from  the  centre 
of  the  track  to  any  part  of  the  trusses  shall  not  be  less  than 
seven  (7)  feet  at  a  height  exceeding  one  foot  above  the  rails 
where  the  tracks  are  straight,  and  an  equivalent  clearance, 
where  the  tracks  are  curved. 

37.  The  standard  distance,  centre  to  centre  of  tracks  on 
straight  lines,  will feet. 

LOADS. 

38.  All  the  structures  shall  be  proportioned  to  carry  the 
following  loads: 

i st.  The  weight  of  metal  in  the  structure  and  floor. 


2d.  The  weight  of  the  paving  and  concrete  or  the 
wooden  floor,  considering  each  foot  of  board  measure  to 
weigh  4^  pounds  for  oak  and  other  hard  woods,  and  3^ 
pounds  for  spruce  and  white  pine. 

These  two  items,  taken  together,  shall   constitute  "  the  Dead 
dead  load." 

3d.  A  "  live  "  or  moving  load,  according  to  one  of  the  Live  Load*, 
following  classes : 

Class  Ai  and  Class  A2.— City  Bridges  : 
For  the  floor  and  its  supports,  on  any  part  of  the  road- 
way or  on  each  of  the  street  car  tracks,  a  concentrated  load 
of  24  tons  on  two  axles  10  feet  centres  (assumed  to  occupy 
12  feet  in  width  for  a  single  line  and  22  feet  for  a  double 
line),  and  upon  the  remaining  portion  of  the  floor,  including 
footwalks,  a  load  of  100  pounds  per  square  foot. 
For  the  trusses,  loads  as  per  Table  A. 
Class  B. — Suburban  or  Interurban  Bridges: 
For  the  floor  and  its  supports,  on  any  part  of  the  road- 
way, a  concentrated  load  of  12  tons  on  two  axles  10  feet 
centres  or  on  each  of  the  street  car  tracks  a  concentrated 
load  of  24  tons  on  two  axles  10  feet  centres  ;  and  upon  the 
remaining  portion  of  the  floor,  including  footwalks,  a  load 
of  100  pounds  per  square  foot  of  floor. 
For  the  trusses,  loads  as  per  Table  A. 
Class  C.— (Class  62  of  former  editions) : 
For  the  floor  and  its  supports,  on  any  part  of  the  road- 
way, a  concentrated  load  of  12  tons  on  two  axles  10  feet 
centres,  or  on  street  car  track  a  concentrated  load  of  18 
tons  on  two  axles  10  feet  centres  ;  and  upon  the  remaining 
portion  of  the  floor,  including  footwalks,  a   load    of    100 
pounds  per  square  foot  of  floor. 

For  the  trusses,  loads  as  per  Table  A. 
Class  D. — (Class  C  of  former  editions.)     Country  High- 
way Bridges  : 

For  the  floor  and  its  supports,  a  load  of  80  pounds  per 
square  foot  of  total  floor  surface,  or  6  tons  on  two  axles  10 
feet  centres. 

For  the  trusses,  loads  as  per  Table  A. 


8 


Class  Ei. — Electric  Railway  Bridges,  with  Heavy  Equip- 
ment : 

For  the  floor  and  its  supports,  a  load  of  24  tons  on  two 
axles  10  feet  centres,  on  each  track. 

For  the  trusses,  loads  as  per  Table  A. 

Class  £2. — Electric  Railway  Bridges,  with  Light  Equip- 
ment : 

For  the  floor  and  its  supports,  a  load  of  18  tons  on  two 
axles  10  feet  centres,  on  each  track. 

For  the  trusses,  loads  as  per  Table  A. 

TABLE  A. — LIVE  LOADS  FOR  THE  TRUSSES. 


CLASS  A. 

CLASS  B. 

Span  in  feet. 

Pounds  per 
lineal  foot  of 
each   car 
track. 

Pounds  per 
square  foot 
of  remaining 
floor  surface. 

Span  in  feet. 

Pounds  per 
lineal  foot  of 
each   car 
track. 

Pounds  per 
square  foot 
of  remaining 
floor  surf  ace. 

%0° 

800 

100 

100 

1  800 

80 

105 

770 

99 

105 

1  770 

79 

110  

.740 

98 

no-  .  . 

1  740 

78 

115 

710 

97 

115 

1  710 

77 

120... 

680 

96 

120  

1  680 

76 

125 

650 

95 

125 

1  6CO 

75 

130... 

620 

94 

130... 

1  620 

74 

135     . 

590 

93 

135     . 

1  590 

73 

140 

560 

92 

140 

1  560 

72 

145... 

530 

91 

145  .. 

1  530 

71 

150 

500 

90 

150 

1  500 

70 

155  

470 

89 

155  .. 

1  470 

69 

160 

440 

88 

160 

1  440 

68 

165... 

410 

87 

165  .. 

1  410 

67    ' 

170 

380 

86 

170 

1  380 

66 

175 

350 

85 

175 

1  350 

65 

180  .. 

320 

84 

180 

1  320 

64 

185 

290 

83 

185 

1  290 

63 

190  

260 

82 

190  .. 

1  260 

62 

195 

1  230 

81 

195 

1  230 

61 

200  and  over... 

1  200 

80 

200  and  over. 

1  200 

60 

CLASS  C. 


X10... 

1  200 

80 

155 

1  090 

69 

105 

1  190 

79 

160 

1  089 

68 

110... 

1  180 

78 

165  .. 

1  070 

67 

115  .. 

1  170 

77 

170 

1  060 

66 

120 

1  160 

76 

175 

1  050 

65 

125... 

1  150 

75 

180 

1  040 

64 

130. 

1  140 

74 

185 

1  030 

63 

135... 

1  130 

73 

190  

1  020 

62 

140 

1  120 

72 

195 

1  010 

61 

145 

1  110 

71 

200  and  over 

1  000 

60 

150  

1  100 

70 

9 


TABLE  A  (Continued) — LIVE  LOADS  FOB  THE  TBUSSES. 


CLASS  D. 

CLASS  E  1. 

CLASS  E  2. 

Span  in  feet. 

Pounds  per 
square  foot 
of  floor 
surface. 

Span  in  feet. 

Pounds  per 
lineal  foot  of 
each  car 
track. 

Span  in  feet. 

Pounds  per 
lineal  foot  of 
each  car 
track. 

Up  to 
75 

80 
79 
78 
77 
76 
75 
74 
73 
72 
71 
70 
69 
68 
67 
66 
65 
64 
63 
62 
61 
60 
59 
58 
57 
56 
55 

Up  to 
100 

1  800 
1  770 
1  ?40 
1  710 
1  680 
1  650 
1  620 
590 
560 
530 
5(10 
470 
440 
410 
380 
1  350 
1  320 
1  290 
1  260 
1  230 
1  200 

Up  to 

100 

1  200 
190 
180 
170 
160 
150 
140 
130 
120 
110 
100 
090 
080 
070 
060 
050 
040 
1  030 
1  020 
1  010 
1  000 

80.... 

105.. 

105 

85. 

110 

110 

90... 

115  . 

115 

95 

IsiO 

120 

100.... 

125  . 

125 

105  . 

130 

130 

no... 

135 

135 

115  

140  

140  . 

120... 

145 

145 

125  

150  

150... 

130... 

155 

155 

135  

I     160... 

160 

140.,. 

165 

165 

145  

170  

170 

150.... 

175 

175 

155  

180  

180 

160. 

185 

185 

165  

190  

190 

170  
175... 

195  

195  

200  and  over. 

200  and  over. 

180 

18SL  

190  .. 

195  

200  and  over. 

The  maximum  strains  due  to  all  positions  of  either  of  the 
above  "live  loads,"  of  the  required  class,  and  of  the  "dead 
loads,"  shall  be  taken  to  proportion  all  the  parts  of  the 
structure. 

39.  To  provide  for  wind  strains  and  vibrations,  the  top  wind  Bracing 
lateral  bracing  in  deck  bridges,  and  the  bottom  lateral  brae- 

ing  in  through  bridges,  shall  be  proportioned  to  resist  a 
lateral  force  of  300  pounds  for  each  foot  of  the  span  ;  150 
pounds  of  this  to  be  treated  as  a  moving  load. 

The  bottom  lateral  bracing  in  deck  bridges,  and  the  top 
lateral  bracing  in  through  bridges,  shall  be  proportioned  to 
resist  a  lateral  force  of  150  pounds  for  each  lineal  foot. 
For  spans  exceeding  300  feet,  add  in  each  of  the  above 
cases  10  pounds  additional  for  each  additional  30  feet. 

40.  In  trestle  towers  the  bracing  and  columns  shall  be 
proportioned    to    resist    the    following   lateral    forces,    in 
addition  to  the  strains  from  dead  and  live  loads: 


10 

The  trusses  loaded  or   unloaded,   the   lateral  pressures 
specified  above  ;  and  a  lateral  pressure  of  100  pounds  for 
each  vertical  lineal  foot  of  the  trestle  bents. 
Temperature.     41 .  Variation  in  temperature,  to  the  extent  of  1 50  degrees, 

shall  be  provided  for. 
Centrifugal     A2.  For  electric  railways  on  curves,  the  additional  effects 

Force 

due  to  the  centrifugal  force  of  cars  single  or  coupled  shall 
be  considered  as  a  live   load.     It  will   be  assumed  to  act  5 
feet  above  base  of  rail,  and  will  be  computed  for  a  speed  of 
40  miles  per  hour. 
Longitudinal     43.  The  strains   produced   in  the  bracing  of  the  trestle 

Forces  .  5    . 

towers,  in  any  members  of  the  trusses,  or  in  the  attach- 
ments of  the  girders  or  trusses  to  their  bearings,  by  sud- 
denly stopping  the  maximum  electric  car  trains  on  any  part 
of  the  work  must  be  provided  for;  the  coefficient  of  friction 
of  the  wheels  on  the  rails  being  assumed  as  0.20. 

44.  All  parts  shall  be  so  designed  that  the  strains  coming 
upon  them  can  be  accurately  calculated. 

PROPORTION  OF   PARTS. 

Tensile  strain.     45.  All  parts  of  the  structures  shall  be  proportioned  in 
tension  by  the  following  allowed  unit  strains: 

Medium  Steel.  For    Medium    Steel.  Pounds  per 

square  inch. 

Floor  beam  hangers,  and  other  similar  members 

liable  to  sudden  loading,  net  section _  8,000 

Longitudinal,  lateral  and  sway  bracing,  for  wind 

and  live  load  strains  (§§  6,  39,  40) 18,000 

Solid  rolled  beams,  used  as  cross  floor  beams  and 

stringers 1 3,000 

Bottom  flanges  of  riveted  girders,  net  section 13,000 

Bottom  chords,  main  diagonals,  counters   nve  loads.    dead°ioads. 
and  long  verticals.. 12,500      25,000 

For  swing  bridges  and  other  movable  structures,  the  dead 
load  unit  strains,  during  motion,  must  not  exceed  three- 
fourths  of  the  above  allowed  unit  strains  for  dead  load  on 
stationary  structures. 

Soft  steei.      Soft  Steel  may  be  used  in  tension  with  unit  strains  ten 
per  cent,  less  than  those  allowed  for  Medium  Steel. 


11 

46.  Angles  subject  to  direct  tension  must  be  connected 
by  both  legs,  or  the  section  of  one  leg  only  will  be  con- 
sidered as  effective. 

47.  In  members  subject  to  tensile  strains  full  allowance  Net  section, 
shall  be  made  for  reduction  of  section  by  rivet-holes,  screw- 
threads,  etc.     (§§  75,  79.) 

48.  Compression  members  shall  be  proportioned  by  the  sSrsessive 
following  allowed  unit  strains  : 

For  Medium  Steel. 

j  Medium  Steel. 

Chord  segments  P=  12,000— 55— for  live  load  strains. 

P=24,ooo — no— for  dead  load  strains. 
r 


All     posts    of  j 

through      P=io,ooo—  45  —  for  live  load  strains. 
bridges. 

7^=20,000  —  90_for  dead  load  strains. 
r 

All     posts     of  i 

deck  bridges      P=II,OOO  —  40  —  for  live  load  strains. 
and  trestles. 

7^=22,000—  80—  for  dead  load  strains. 
r 

End  posts  are  not  to  be  considered  chord  segments. 

Lateral  struts  j 

and    rigid     /*=  13,000  —  60  —  for  wind  strains; 
bracing. 

for  live  load  strains  use  two-thirds  of  the  above.    (§§  42,  43, 
124.) 


allowed  strain  in  compression  per  square  inch  of 
cross-section,  in  pounds. 

/=the  length  of  compression  member,  in  inches,  c.  to  c.  , 
of  connections. 

r=the  least  radius  of  gyration  of  the  section,  in  inches. 

No  compression  member,  however,  shall  have  a  length 


12 

exceeding   100  times  its  least  radius  of  gyration  for  main 
members,  or  120  times  for  laterals. 

For  swing  bridges  and  other  movable  structures,  the 
dead  load  unit  strains  during  motion  must  not  exceed  J  of 
the  above  allowed  unit  strains  for  dead  load  on  stationary 
structures. 

49.  For  long  span  bridges,  when  the  ratio  of  the  length 
and  width  of  span  is  such  that  it  makes  the  top  chords  acting 
as  a  whole,  a  longer  column  than  the  segments  of  the  chord, 
the  chord  will  be  proportioned  for  this  greater  length. 

Soft  steei.     Soft  Steel  may  be  used  in  compression  with  unit  strains 
fifteen  per  cent,  less  than  those  allowed  for  Medium  Steel. 

50.  The  areas  obtained  by  dividing  the  live  load  strains  by 
the  live  load  unit  strains  will  be  added  algebraically  to  the 
areas  obtained  by  dividing  the  dead  load  strains  by   the 
dead  load  unit  strains  to  determine  the  required  sectional 
area  of  any  member.     (§  62.) 

Alternate      51.  All  members  and  their  connections  subject  to  alter- 

Strains.  ~      •    '  r  •  i  *  1111 

nate  strains  of  tension  and  compression  shall  be  propor- 
tioned to  resist  each  kind  of  strain.     Both  of  the  strains  shall, 
however,  be  considered  as  increased  by  an  amount  equal  to 
j\  of  the  least  of  the  two  strains,  for  determining  the   sec- 
tional areas  by  the  above-allowed  unit  strains.     (§§45,48.) 
Effect  of  wind      52.  The  strains  in   the  truss   members  or   trestle   posts 
stains.         from  the  assumed  wind  forces  need  not  be  considered  ex- 
cept as  follows : 

ist.  When  the  wind  strains  on  any  member  exceed  25 
per  cent,  of  the  maximum  strains  due  to  the  dead  and  live 
loads  upon  the  same  member.  The  section  shall  then  be 
increased  until  the  total  strain  per  square  inch  will  not 
exceed  by  more  than  25  per  cent,  the  maximum  fixed  for 
dead  and  live  loads  only. 

2d.  When  the  wind  strain  alone  or  in  combination  with  a 
possible  temperature  strain,  can  neutralize  or  reverse  the 
strains  in  any  member. 

Rivets,  Bolts  53.  The  rivets  in  all  members,  other  than  those  of  the 
floor  and  lateral  systems,  must  be  so  spaced  that  the  shear- 
ing strain  per  square  inch  shall  not  exceed  10,000  pounds; 


13 

nor  the  pressure  on  the  bearing  surface  (diameter  X  thick- 
ness of  the  piece)  of  the  rivet-hole  exceed  18,000  pounds 
per  square  inch. 

The  rivets  in  all  members  of  the  floor  system,  including 
all  hanger  connections,  must  be  so  spaced  that  the  shearing 
strains  and  bearing  pressures  shall  not  exceed  80  per  cent. 
of  the  above  limits. 

The  rivets  in  the  lateral  and  sway  bracing  will  be  allowed 
40  per  cent,  increase  upon  the  above  limits. 

In  the  case  of  field  riveting  (and  for  bolts  as  per  §  76)  the 
above-allowed  shearing  strains  and  pressures  shall  be  re- 
duced one-third. 

Rivets  and  bolts  must  not  be  used  in  direct  tension. 

54.  Pins  shall  be  proportioned  so  that  the  shearing  strain 
shall  not  exceed    10,000  pounds  per  square  inch  ;   nor  the 
pressure  on  the  bearing  surface  of  any  member  (other  than 
forged  eye-bars,  see  §  104)  connected  to  the  pin  be  greater 
per  square  inch  than  18,000  pounds  ;  nor  the  bending  strain 
exceed  20,000  pounds,  when  the  applied  forces  are  consid- 
ered as  uniformly  distributed  over  the  middle  half  of  the 
bearing  of  each  member. 

55.  When  any  member  is  subjected  to  the  action  of  both  combined 
axial  and  bending  strains,  as  in  the  case  of   end  posts  of  St 
through    bridges  (§  52),  or  of  chords  carrying  distributed 
floor  loads,  it  must   be  proportioned   so  that  the  greatest 
fibre  strain  will  not  exceed  the  allowed  limits  of  tension  or 
compression  on  that  member. 

If  the  fibre  strain  resulting  from  the  weight  only,  of  any 
member,  exceeds  ten  per  cent,  of  the  allowed  unit  strain  on 
such  member,  such  excess  must  be  considered  in  propor- 
tioning the  areas. 

56.  In  beams  and  plate  girders  the  compression  flanges  compression 
shall  be  made  of  same  gross  section  as  the  tension  flanges. 


57.  Riveted  longitudinal  girders  shall  have,  preferably,  a 
depth  not  less  than  ^  of  the  span. 

Rolled  beams  used  as  longitudinal  girders  shall    have, 
preferably,  a  depth  not  less  than  -g1^  of  the  span. 

58.  Plate  girders  shall  be  proportioned  upon  the  supposi-  Plate  Girders 


14 

tion  that  the  bending  or  chord  strains  are  resisted  entirely 
by  the  upper  and  lower  flanges,  and  that  the  shearing  or 
web  strains  are  resisted  entirely  by  the  web-plate ;  no  part 
of  the  web-plate  shall  be  estimated  as  flange  area. 

The  distance  between  centres  of  gravity  of   the  flange 
areas  will  be  considered  as  the  effective  depth  of  all  girders. 
web  piates.      50,.  The  webs  of  plate  girders  must  be  stiffened  at  inter- 
vals, not  exceeding  the  depth  of  the  girders  or  a  maximum 
of  5  feet,  wherever  the  shearing  strain  per  square  inch  .ex- 
ceeds the  strain  allowed  by  the  following  formula  : 
Allowed  shearing  strain  =  12,500  —  9O//, 
where  H  =  ratio  of  depth  of  web  to  its  thickness  ;  but  no 
web-plates  shall  be  less  than  T5^  of  an  inch  in  thickness, 
stiffeners.     60.  All  stiffeners  must  be  capable  of  carrying  the  maximum 
vertical  shear  without  exceeding  the  allowed  unit  strain. 

P=  12,000—  55-. 

Each  stiffener  must  connect  to  the  webs  by  enough  rivets 
to  transfer  the  maximum  shear  to  or  from  the  webs  (§  83). 
Roiled  Beams.     61.  Rolled  beams  shall  be  proportioned   (§§  45,  48)   by 

their  moments  of  inertia. 

Counters.  62.  The  areas  of  counters  shall  be  determined  by  taking 
the  difference  in  areas  due  to  the  live  and  dead  load  strains 
considered  separately  (§  45,  105). 

63.  For  bridges  carrying  electric  or  motor  cars  counters 
shall  be  provided  and  proportioned,  so  that  a  future  increase 
of  25  per  cent,  in  the  specified  live  load  shall  not  in  any  case 
increase  the  allowed  unit  strain  more  than  25  per  cent. 

DETAILS  OF  CONSTRUCTION. 

Details.  64.  All  the  connections  and  details  of  the  several  parts  of 
the  structures  shall  be  of  such  strength  that,  upon  testing, 
rupture  will  occur  in  the  body  of  the  members  rather 
than  in  any  of  their  details  or  connections. 

65.  Preference  will  be  had  for  such  details  as  shall  be 
most  accessible  for  inspection,  cleaning  and  painting  ;  no 
closed  sections  will  be  allowed. 

66.  The  pitch  of  rivets  in  all  classes  of  work  shall  never 


15 

exceed  6  inches,  or  sixteen  times  the  thinnest  outside  plate, 
nor  be  less  than  three  diameters  of  the  rivet. 

67.  The  rivets  used  shall  generally  be  f  and  |  inch  diameter. 

68.  The  distance  between  the  edge  of  any  piece  and  the 
centre  of  a  rivet-hole  must  never  be  less  than  ij  inches, 
except  for  bars  less  than  2\  inches  wide  ;  when  practicable 
it  shall  be  at  least  two  diameters  of  the  rivet. 

69.  For  punching,  the  diameter  of  the  die  shall  in  no  case 
"exceed  the  diameter  of  the  punch  by  more  than  T*g-  of  an 

inch,   and  all   holes  must    be  clean  cuts  without    torn  or 
ragged  edges. 

70.  All   rivet   holes  must    be   so  accurately  spaced  and 
punched  that  when  the  several  parts  forming  one  member 
are  assembled  together,  a  rivet  y1^  inch  less  in  diameter  than 
the  hole  can  generally  be  entered,  hot,  into  any  hole,  with- 
out reaming  or  straining  the  metal  by  "  drifts  ";  occasional 
variations  must  be  corrected  by  reaming. 

71.  The    rivets    when   driven    must  completely   fill   the 
holes.     The  rivet-heads  must  be  round  and  of  a  uniform  size 
for  the  same  sized  rivets  throughout  the  work.     They  must 
be  full  and  neatly  made,  and  be  concentric  to  the  rivet-hole, 
and  thoroughly  pinch  the  connected  pieces  together. 

72.  Wherever  possible,  all  rivets  must  be  machine  driven. 
The  machines  must    be   capable  of   retaining  the  applied 
pressure  after  the  upsetting  is  completed.     No  hand-driven 
rivets  exceeding  J  inch  diameter  will  be  allowed. 

73.  Field  riveting  must   be  reduced    to  a   minimum  or 
entirely  avoided,  where  possible. 

74.  All  holes  for  field  rivets,  except  those  in  connections 
of  the  lateral  and  sway  systems,  shall  be  accurately  drilled 
or  reamed  to  an  iron  template  or  be  reamed  true  while  the 
parts  are  temporarily  connected  together. 

75.  The  effective  diameter  of  a  driven  rivet  will  be  as-  N«  Sections. 
sumed  the  same  as  its  diameter  before  driving.     In  deduct- 
ing the  rivet-holes  to  obtain  net  sections  in  tension  mem- 
bers, the  diameter  of  the  rivet-holes  will  be  assumed  as  -J 

inch  larger  than  the  undriven  rivets. 

The  rupture  of  a  riveted  tension  member  is  to  be  con- 


16 

sidered  as  equally  probable,  either  through  a  transverse 
line  of  rivet-holes  or  through  a  diagonal  line  of  rivet-holes, 
where  the  net  section  does  not  exceed  by  30  per  cent,  the 
net  section  along  the  transverse  line. 

The  number  of  rivet-holes  to  be  deducted  for  net  section 
will  be  determined  by  this  condition.  (§§  47-79.) 
Bolts.  76.  When  members  are  connected  by  bolts  the  holes  must 
be  reamed  parallel  and  the  bolts  turned  to  a  driving  fit. 
All  bolts  must  be  of  neat  lengths,  and  shall  have  a  washer 
under  the  heads  and  nuts  where  in  contact  with  wood. 
Bolts  must  not  be  used  in  place  of  rivets,  except  by  special 
permission. 

77.  All  nuts  must  be  of  hexagonal  shape. 

splices.     78.  All  joints  in  riveted  tension   members  must  be  fully 
and  symmetrically  spliced. 

79.  Riveted  tension  members  shall  have  an  effective  sec- 
tion through  the  pin-holes  25  per  cent,  in  excess  of  the  net 
section  of  the    member,  and  back  of  the  pin  at   least   75 
per  cent,  of  the  net  section  through  the  pin-hole. 

80.  In  continuous  compression  members,  as  chords  and 
trestle  posts,  the  abutting  joints  with  planed  faces  must  be 
placed  as  close  to  the  panel  points  as  is  practicable,  and  the 
joints  must  be  spliced  on  all  sides  with  at  least  two  rows  of 
closely  pitched  rivets  on  each  side  of  the  joint. 

Joints  in  long  posts  must  be  fully  spliced. 

Abutting  joints.  8 1.  In  compression  members,  abutting  joints  with  un- 
tooled  faces  must  be  fully  spliced,  as  no  reliance  will  be 
placed  on  such  abutting  joints.  The  abutting  ends  must, 
however,  be  dressed  straight  and  true,  so  there  will  be  no 
open  joints. 

82.  The  webs  of  plate  girders  must  be  spliced  at  all  joints 
by  a  plate  on  each  side  of  the  web. 

83.  All   web-plates    must   have   stiffeners    over    bearing 
points  and  at  points  of  local  concentrated  loadings ;  such 
stiffeners  must  be  fitted  at  their  ends  to  the  flange  angles, 
at  the  bearing  points.     (§§  59-60.) 

84.  All  other  angles,  filling  and  splice  plates  on  the  webs 
of  girders  and  riveted  members   must  fit  at  their  ends  to 


17 

the    flange    angles,    sufficiently  close    to    be   sealed,  when 
painted,  against  admission  of  water. 

85.  Web-plates  of  all  girders  must- be  arranged  so  as  not  Web  Plates, 
to  project  beyond  the  faces  of  the  flange  angles,  nor  on  the 

top  be  more  than  -fa  inch   below  the  face  of  these  angles,  at 
any  point. 

86.  Wherever  there  is  a  tendency  for  water  to  collect, 
the  spaces  must  be  filled  with  a  suitable  waterproof  material. 

87.  In  girders  with  flange  plates,  at  least  one-half  of  the  Flange  Plates. 
flange  section  shall  be  angles  or  else  the  largest  sized  angles 

must   be   used.     Flange  plates   must  extend   beyond  their 
theoretical  length,  two  rows  of  rivets  at  each  end. 

88.  The  flange  plates  of   all  girders  must  be  limited  in 
width  so  as  not  to  extend  beyond  the  outer  lines  of  rivets 
connecting  them  with  the  angles,  more   than  five  inches  or 
more  than  eight  times  the  thickness  of  the  first  plate.   Where 
two  or  more  plates  are  used  on  the  flanges,  they  shall  either 
be  of  equal  thickness  or  shall  decrease  in  thickness  outward 
from  the  angles. 

80.   The  compression  flanges  of  beams  and  girders  shall  be  Compression 

,  -i-  1      •       i  i      •     Flanges. 

stayed  against    transverse    crippling  when  their  length  is 
more  than  sixteen  times  their  width. 

90.  The  unsupported  width  (distance  between  rivets)  of  width  oi 
plates  subject  to  compression  shall  not  exceed  thirty  times 
their  thickness ;  except  cover  plates  of  top  chords  and  end 
posts,  which  will  preferably  be  limited  to  forty  times  their 
thickness  ;  where  a  greater  relative  width  is  used  in  chords 

and    end    posts,    however,    only  forty  times  the  thickness 
shall  be  considered  as  effective  section. 

91.  In  lattice  girders  and  trusses  the  web  members  must 
be  double  and  connect  symmetrically  to  the  webs  of  the 
chords.     The  use  of  plates  or  flats,  alone,  for  tension  mem- 
bers   must    be    avoided,  where    it   is    possible;    in    lattice 
trusses,  the    counters,  suspenders    and    two   panels  of  the 
lower  chord,  at  each   end,  must  be  latticed ;  all  other  ten- 
sion members  must  be  connected  by  batten  plates  or  latticed. 

(§  I"-) 

92.  Where  the  floor  timbers  are  supported  at  their  ends 


18 

on  the  flange  of  one  angle,  such  angle  must  have  two  rows 
of  rivets  in  its  vertical  leg,  spaced  not  over  4  inches  apart. 
Buckle  Plates.  93.  Buckle  plates  must  be  firmly  riveted  to  the  support- 
ing beams  and  be  spliced  at  all  free  edges.  Preferably 
they  will  be  made  in  continuous  sheets  of  panel  lengths. 
They  may  be  pressed  or  formed  without  heating.  (§  23.) 

94.  A  buckle-plate  floor,  as  specified,  may  be  considered 
as  the  required  lateral  system  of  bracing  at  the  floor  level. 

95.  The  buckle-plates  of  the  sidewalks  will  be  covered  to 
the  proper  slope  and  level  for  the  wearing  pavement  with 
bitumen  concrete  of  an  accepted  and  waterproof  character. 

96.  The  buckle-plates  of  the  roadway   will  be  covered 
with  an  acceptable  and  waterproof  concrete  (bitumen  or 
cement)  to  the  proper  crown  and  grade  for  the  wearing 
pavement,  but  at  no  place  must  the  concrete  be  less  than  3 
inches  thick. 

Thickness  of  97-  For  main  members  and  their  connections  no  material 
shall  be  used  of  a  less  thickness  than  T57  of  an  inch ;  and  for 
laterals  and  their  connections,  no  material  less  than  J  of 
an  inch  in  thickness  ;  except  for  lining  or  filling  vacant 
spaces.  No  bars  shall  be  used  with  a  less  net  area  than  j 
of  one  square  inch. 

Eye  Bars  98.  The  heads  of  eye-bars  shall  be  so  proportioned  and 
made,  that  the  bars  will  preferably  break  in  the  body  of 
the  original  bar  rather  than  at  any  part  of  the  head  or  neck. 
The  form  of  the  head  and  the  mode  of  manufacture  shall  be 
subject  to  the  approval  of  the  Engineer.  (§§138,  139,  159, 
1 60.) 

99.  The  bars  must  be  free  from  flaws  and  of  full  thick- 
ness in  the  necks.     They  shall  be  perfectly  straight  before 
boring.     The  holes  shall  be  in  the  centre  of  the  head,  and 
on  the  centre  line  of  the  bar. 

100.  The  bars  must  be  bored  to  lengths  not  varying  from 
the  calculated  lengths  more  than  -fa  of  an  inch  for  each  25 
feet  of  total  length. 

101.  Bars  which  are   to   be  placed   side  by  side  in  the 
structure  shall  be  bored  at  the  same  temperature  and  of 
such  equal  length  that  upon  being  piled  on  each  other  the 


19 

pins  shall  pass  through  the  holes  at  both  ends  without 
driving. 

102.  The  lower  chord  shall  be  packed  as  narrow  as  possi- 
ble. 

103.  The  pins  shall  be  turned  straight  and  smooth  ;  chord  pins. 
pins  shall  fit  the  pin-holes  within  -£-$  of  an  inch,  for  pins  less 
than  4^  inches  diameter ;  for  pins  of  a  larger  diameter  the 
clearance  may  be  -fa  inch. 

104.  The  diameter  of  the  pin  shall  not  be  less  than  three- 
quarters  the  largest  dimension  of  any  eye-bar  attached  to  it. 
The   several    members   attaching   to   the    pin  shall    be  so 
packed  as  to  produce  the  least  bending  moment  upon  the 
pin,  and  all  vacant  spaces  must  be  filled  with  wrought  fill- 
ing rings. 

105.  All  bars  with  screw  ends  shall  be  upset  at  the  ends,  Upset  Ends, 
so  that  the  diameter  at  the  bottom  of  the  threads  shall  be 

Y1^  inch  larger  than  any  part  of  the  body  of  the  bar.  Where 
closed  sleeve  nuts  are  used  on  adjustable  members  the 
effective  length  of  thread  shall  be  legibly  stamped  at  the 
screw  ends  of  each  bar.  Adjustable  counters  to  be  avoided 
where  practicable. 

106.  All  threads  must  be  of  the  United  States  standard, 
except  at  the  ends  of  the  pins. 

107.  Floor  beam  hangers  when  permitted  shall  be  made  Hangers. 
without  adjustment  and  so  placed  that  they  can  be  readily 
examined  at  all  times.     (§  3.) 

108.  All  the  floor  beams  must  be  effectually  stayed  against 
end  motion  or  any  tendency  to  rotate  from  the  action  of  the 
lateral  system. 

IOQ.  Compression  members  shall  be  of  steel,  and  of  ap- Compression 

y   ,    .  Members. 

proved  forms. 

1 10.  The  pitch  of  rivets  at  the  ends  o<  compression  mem- 
bers shall  not  exceed  four  diameters  of  the  rivets  for  a 
length  equal  to  twice  .the  width  ot  the  member. 

in.  The  open  sides  of  all  compression  members  shall  be 
stayed  by  batten  plates  at  the  ends  and  diagonal  lattice- 
work at  intermediate  points.  The  batten  plates  must  be 
placed  as  near  the  ends  as  practicable,  and  shall  have  a 


20 

length  not  less  than  the  greatest  width  of  the  member  or  i £ 
times  its  least  width.  The  size  and  spacing  of  the  lattice 
bars  shall  be  duly  proportioned  to  the  size  of  the  member. 
They  must  not  be  less  in  width  than  i|  inches  for  mem- 
bers 6  inches  t  in  width,  if  inches  for  members  9  inches  in 
width,  2  inches  for  members  12  inches  in  width,  nor  2\ 
inches  for  members  15  inches  in  width,  nor  2\  inches  for 
members  18  inches  and  over  in  width.  Single  lattice  bars 
shall  have  a  thickness  not  less  than  ^  or  double  lattice  bars 
connected  by  a  rivet  at  the  intersection,  not  less  than  -^  of 
the  distance  between  the  rivets  connecting  them  to  the 
members.  They  shall  be  inclined  at  an  angle  not  less  than 
60°  to  the  axis  of  the  member  for  single  latticing,  nor  less 
than  45°  for  double  latticing  with  riveted  intersections. 
The  pitch  of  the  latticing  must  not  exceed  the  width  of  the 
channel  plus  nine  inches. 

112.  Where   necessary,  pin-holes  shall  be  reinforced   by 
plates,   some  of   which  must  be  of  the  full  width  of  the 
member,  so  the  allowed  pressure  on  the  pins  shall  not  be 
exceeded,  and  so  the  strains  shall  be  properly  distributed 
over  the  full  cross-section  of  the  members.    These  reinforc- 
ing plates  must  contain  enough  rivets  to  transfer  their  pro- 
portion of  the  bearing  pressure,  and  at  least  one  plate  on 
each  side  shall  extend  not  less  than  six  inches  beyond  the 
edge  of  the  batten  plates.     (§  in.) 

113.  Where  the  ends  of  compression  members  are  forked 
to  connect  to  the  pins,  the  aggregate  compressive  strength 
of  these  forked  ends  must  equal  the  compressive  strength 
of  the  body  of  the  members. 

114.  In  compression  chord  sections  and   end  posts,  the 
material  must  mostly  be  concentrated  at  the  sides,  in  the 
angles  and  vertical  *webs.     Not  more  than  one  plate,  and 
this  not  exceeding  f  inch  in  thickness,  shall  be  used  as  a 
cover  plate,  except'when  necessary  to  resist  bending  strains, 
or  to  comply  with  §  90.     (§55.) 

115.  The   ends   of    all  square-ended    members    shall    be 
planed  smooth,  and  exactly  square  to   the   centre   line   of 
strain. 


21 

116.  The  ends  of  all  floor  beams  and  stringers  shall  be  Floor  Beams 
faced  true  and  square,  and  to  correct  lengths.     Allowance™ 
must  be  made  in  the  thickness  of  the  end  angles  to  provide 

for  such   facing   without  reducing  the  required   effective 
strength  of  such  end  angles. 

117.  All  members  must  be  free  from  twists  or  bends.    For- 
tions  exposed  to  view  shall  be  neatly  finished. 

118.  Pin-holes  shall  be  bored  exactly  perpendicular  to  apin-Hoies. 
vertical  plane  passing  through  the  centre  line  of  each  mem- 
ber, when  placed  in  a  position  similar  to  that  it  is  to  occupy 

in  the  finished  structure. 

119.  The  several  pieces  forming  one  built  member  must 
fit  closely  together,  and  when  riveted  shall  be  free  from 
twists,  bends  or  open  joints. 

1 20.  All  through  bridges  shall  have  latticed  portals,  of  Transverse 
approved  design,  at  each  end  of  the  span,  connected  rigidly  Bracing 

.to  the  end  posts  and  top  chords.  They  shall  be  as  deep  as 
the  specified  head-room  will  allow,  and  provision  shall  be 
made  in  the  end  posts  for  the  bending  strains  from  wind 
pressure.  (§§4,  10,  39,  52.) 

121.  When  the  height  of  the  trusses  exceeds  20  feet,  an 
approved  system  of  overhead    diagonal  bracings  shall  be 
attached  to  each  post  and  to  the  top  lateral  struts. 

122.  Knee   braces  shall   be  placed  at  each  intermediate 
panel  point,  and  connected  to  the  vertical  posts  and  top 
lateral  struts,  for  trusses  20  feet  and  less  in  depth. 

123.  Pony  trusses  and   through  plate  or  lattice  girders 
shall  be  stayed  by  knee  braces  or  gusset  plates  attached  to 
the  top  chords  at  the  ends  and  at  intermediate  points,  and 
attached  below  to  the  cross  floor  beams  or  to  the  transverse 
struts. 

124.  All  deck  girders  shall  have  transverse  braces  at  the 
ends.     All  deck  bridges  shall   have  transverse  bracing  at 
each  panel  point.     This  bracing  shall  be  proportioned  to 
resist  the  unequal  loading  of  the  trusses. 

125.  All  members  of  the  web,  lateral,  longitudinal  or  sway 
systems  must  be  securely  riveted  at  their  intersections  to 
prevent  sagging  and  rattling. 


22 

Bed  Plates.  126.  All  bed-plates  must  be  of  such  dimensions  that  the 
greatest  pressure  upon  the  pedestal  stone  shall  not  exceed 
250  pounds  per  square  inch. 

Friction  I2/.  All  bridges  over  80  feet  span  shall  have  hinged 
rs' bolsters  on  both  ends,  and  at  one  end  nests  of  turned  fric- 
tion rollers  running  between  planed  surfaces.  These  rollers 
shall  not  be  less  than  2-J  inches  diameter  for  spans  100  feet 
or  less,  and  for  greater  spans  this  diameter  shall  be  increased 
in  proportion  of  I  inch  for  100  feet  additional. 

The  rollers  shall  be  so  proportioned  that  the  pressure 
per  lineal  inch  of  roller  shall  not  exceed  the  product  of  the 
diameter  in  inches  by  300  pounds  (3Ood.). 

The  rollers  must  be  of  machinery  steel  and  the  bearing 
plates  of  medium  steel. 

The  rollers  and  bearings  must  be  so  arranged  that  they 
can  be  readily  cleaned  and  so  that  they  will  not  hold  water. 

128.  Bridges  less  than  80  feet  span  shall  be  secured  at 
one  end  to  the  masonry,  and  the  other  end  shall  be  free  to 
move  longitudinally  upon  smooth  surfaces. 

129.  Where  two  spans  rest  upon  the  same  masonry,  a  con- 
tinuous plate,  not  less  than  f  inch  thick,  shall  extend  under 
the  two  adjacent  bearings,  or  the  two  bearings  must  be 
rigidly  tied  together. 

Pedestals  and  130.  Pedestals  shall  be  made  of  riveted  plates  and  angles. 
All  bearing  surfaces  of  the  base  plates  and  vertical  webs 
must  be  planed.  The  vertical  webs  must  be  secured  to  the 
base  by  angles  having  two  rows  of  rivets  in  the  vertical 
legs.  No  base  plate  or  web  connecting  angle  shall  be  less 
in  thickness  than  -J  inch.  The  vertical  webs  shall  be  of 
sufficient  height  and  must  contain  material  and  rivets 
enough  to  practically  distribute  the  loads  over  the  bearings 
or  rollers. 

Where  the  size  of  the  pedestal  permits,  the  vertical  webs 
must  be  rigidly  connected  transversely. 

131.  All  the  bed-plates  and  bearings  under  fixed  and 
movable  ends  must  be  fox-bolted  to  the  masonry  ;  for 
trusses,  these  bolts  must  not  be  less  than  ij  inches  diameter; 
for  plate  and  other  girders,  not  less  than  -J  inch  diameter. 


The  contractor  must  furnish  all  bolts,  drill  all  holes  and  set 
bolts  to  place  with  sulphur  or  Portland  cement. 

132.  While  the  expansion  ends  of  all  trusses  must  be  free 
to  move  longitudinally  under  changes  of  temperature,  they 
shall  be  anchored  against  lifting  or  moving  sideways. 

133.  All  bridges  shall  be  cambered  by  giving  the  panels  Camber, 
of  the  top  chord  an  excess  of  length  in  the  proportion  of 

T3^  of  an  inch  to  every  ten  feet. 

134.  The  lower  struts  in  trestle  towers  must  be  capable  Trestle  Towers, 
of  resisting  the  strains  due  to  changes  of  temperature  or  of 
moving  the  tower  pedestals  under  the  effects  of  expansion 

or  contraction. 

For  high  or  massive  towers,  these  lower  struts  will  be 
securely  anchored  to  intermediate  masonry  piers,  or  the 
tower  pedestals  will  have  suitably  placed  friction  rollers, 
as  may  be  directed  by  the  Engineer. 

135.  All  joints  in  the  tower  columns  shall  be  fully  spliced 
for  all  possible  tension  strains,  and  to  hold  the  parts  firmly 
in  position.     (§  80.) 

136.  Tower   footings  arfd  bed-plates  must  be  planed  on 
all  bearing  surfaces ;  and  the  holes  for  anchor  bolts  slotted 
to  allow  for  the  proper  amount  of  movement.     (§  41.) 

137.  All  workmanship  shall   be  first-class  in   every   par- workmanship, 
ticular. 

138.  All  eye-bars  must  be  made  of  medium  steel.  Eye-Bars. 

139.  Eye-bars,  all   forgings   and  any  pieces  which  have 
been  partially   heated    or  bent   cold    must   be  wholly  an- 
nealed.    Crimped  stiffeners  need  not  be  annealed. 

140.  No   reliance  will   be   placed   upon   the  welding  of 
steel. 

141.  No   sharp   or   unfilleted  angles  or   corners  will   be 
allowed  in  any  piece  of  metal. 

142.  Medium  steel  maybe  used  in  compression  in  chords,  Medium  steel. 
posts  and  pedestals  without  reaming  of  punched   holes,  for 

all  thicknesses  of  metal,  which  will  stand  the  drifting  test 
§  154);  provided  all  sheared  edges  are  planed  off  to  a  depth 
of  £  inch. 

In  all  other  cases  medium  steel  over  f  inch  thick  must 


have  all  sheared  edges  planed  off  to  a  depth  of  |  inch  and 
all  holes  drilled  or  reamed  to  a  diameter  %  inch  larger  than 
the  punched  holes,  so  as  to  remove  all  the  sheared  surface 
of  the  metal. 

Soft  steel.      143.  Soft  steel  need  not  be  reamed  if  it  satisfies  the  drift- 
ing test  (§§  154,  155). 

144.  All  parts  of   any  tension   or  compression  flange  or 
member,  must  be  of   the  same  kind  of  steel,  but  webs  of 
plate  girders  and  the  tension  members  of  all  girders,  plate 
or  lattice,  may  be  made  of  soft  steel  in  connection  with 
compression  members  of  medium  steel. 

145.  All  splices  must  be  of  the  same  kind  of  steel  as  the 
parts  to  be  joined. 

^piiotNuts      146.  Pilot  nuts  must  be  used  during  the  erection  to  pro- 
tect the  threads  of  the  pins. 

QUALITY  OF  MATERIAL. 

STEEL. 

* 

147.  All  steel  must  be  made  by  the  Open  Hearth  process. 
The  phosphorus  must  not  exceed  0.06  of  one  per  cent,  for 
steel  made  by  the  acid  method,  or  0.04  for  steel  by  the  basic 
method. 

148.  The  steel  must  be   uniform  in    character  for   each 
specified  kind.     The  finished   bars,  plates  and  shapes  must 
be  free   from  cracks  on  the  faces  or  corners,  and  have  a 
clean,  smooth  finish.     No  work  shall  be  put  upon  any  steel 
at  or  near  the  blue  temperature  or  between  that  of  boiling 
water  and  of  ignition  of  hard  wood  sawdust. 

149.  The  tensile  strength,  elastic  limit*  and  ductility  shall 
be  determined  by  samples  cut  from  the  finished   material 
after  rolling.     The  samples  to  be  at  least  12  inches  long, 
and  to  have  a  uniform  sectional  area  not  less  than  J  square 
inch. 

*  For  the  purpose  of  these  specifications,  the  Elastic  Limit  will  be  considered  the  least 
strain  producing  a  visible  permanent  elongation  in  a  length  of  8  inches,  as  shown  by  scribe 
marks  of  a  pair  of  finely  pointed  dividers. 

If  the  yield  point  or  drop  of  the  beam  can  be  calibrated  for  any  machine  and  its  speed  to 
represent  the  elastic  limit  within  5  per  cent.,  it  may  be  used  for  general  cases.  Test  reports 
must  state  by  which  method  the  elastic  limit  was  determined. 


""""     I  HE  \ 

UNIVERSITY  ) 


25 

150.  Material  which  is  to  be  used  without  annealing  or 
further  treatment  is  to  be  tested  in  the  condition  in  which 
it  comes  from  the  rolls.     When  material  is  to  be  annealed 
or  otherwise  treated  before  use,  the  specimen  representing 
such  material  is  to  be  similarly  treated  before  testing,  for 
tensile  strength. 

The  elongation  shall  be  measured  on  an  original  length  of 
8  inches.  Two  test  pieces  shall  be  taken  from  each  melt  or 
blow  of  finished  material,  one  for  tension  and  one  for  bend- 
ing, (Art.  166.) 

151.  All  samples  or  full-sized  pieces  must  show  uniform 
fine   grained  fractures  of  a  blue  steel-gray  color,  entirely 
free  from  fiery  lustre  or  a  blackish  cast. 

152.  Medium  Steel  shall  have  an  ultimate  strength,  when  Medium  steel. 
tested  in  samples  of  the  dimensions  above  stated,  of  60,000 

to  68,000  pounds  per  square  inch,  an  elastic  limit  of  not 
less  than  one-half  of  the  ultimate  strength,  and  a  minimum 
elongation  of  22  per  cent,  in  8  inches.  Steel  for  pins  may 
have  a  minimum  elongation  of  15  per  cent. 

153.  Before   or  after   heating   to  a   low  cherry  red  and 
cooling  in  water  at  82  degrees  Fahr.,  this  steel  must  stand 
bending  to  a  curve  whose  inner  radius  is  one  and  a  half 
times  the  thickness  of  the  sample,  without  cracking. 

154.-  For  all  medium  steel,  g  inch  or  less  in  thickness, 
rivet  holes  punched  as  in  ordinary  practice  (§§  68,  69,  70), 
must  stand  drifting  to  a  diameter  one-third  greater  than 
the  original  holes,  without  cracking  either  in  the  periphery 
of  the  holes  or  on  the  external  edges  of  the  piece,  whether 
they  be  sheared  or  rolled. 

155.  Soft  Steel  shall  have  an  ultimate  strength,  on  same  soft  steel, 
sized   samples,   of    54,000    to    62,000    pounds    per   square 
inch,  an  elastic  limit   not   less   than   one-half  the  ultimate 
strength,  and  a  minimum  elongation  of   25  per  cent,  in  8 
inches. 

For  soft  steel  the  above  drifting  test  (§  154)  shall  apply  to 
all  material  to  be  riveted. 

156.  Before  or  after  heating  to  a  light  yellow  heat  and 
quenching  in  cold  water,  this  steel  must  stand  bending  180 


26 

degrees,  to  a  curve  whose  inner  radius  is  equal  to  the 
thickness  of  the  sample,  without  sign  of  fracture. 
Rivet  steei.  jc^  Rivet  Steel  shall  have  an  ultimate  strength  of  50,000 
to  58,000  pounds  per  square  inch,  an  elastic  limit  not  less 
than  one-half  the  ultimate  strength  and  an  elongation  of  26 
per  cent. 

158.  The  steel  for  rivets  must,  under  the  above  bending 
test  (156),  stand  closing  solidly  together  without  sign  of 
fracture. 

Eye  Bars.  159.  Eye-bar  material,  ij  inches  and  less  in  thickness, 
shall,  on  test  pieces  cut  from  finished  material,  fill  the  above 
requirements.  For  thicknesses  greater  than  i-J  inches,  there 
will  be  allowed  a  reduction  in  the  percentage  of  elongation 
of  i  per  cent,  for  each  |  of  an  inch  increase  of  thickness,  to 
a  minimum  of  20  per  cent.  (Art.  138.) 

160.  Full  sized  eye-bars  shall  show  not  less  than  10  per 
cent,  elongation  in  the  body  of  the  bar,  and  an  ultimate 
strength  not  less  than  56,000  pounds  per  square  inch. 
Should  a  bar  break  in  the  head,  but  develop  10  per  cent, 
elongation  and  the  ultimate  strength  specified,  it  shall  not 
be  cause  for  rejection,  provided  not  more  than  one-third  of 
the  total  number  of  bars  tested  break  in  the  head. 
Pins.  161.  Pins  over  7  inches  in  diameter  shall  be  forged. 
Blooms  for  pins  shall  have  at  least  three  times  the  sectional 
area  of  the  finished  pins. 

162.  A  variation  of  cross-section  or  weight  in  the  finished 
members  of  2-J  per  cent,  from  the  specified  size  may  be 
cause  for  rejection. 

STEEL  CASTINGS. 

steei  castings.  163.  Steel  castings  will  be  used  for  drawbridge  wheels, 
track  segments  and  gearing.  (Art.  I.) 

They  must  be  true  to  form  and  dimensions,  of  a  work- 
manlike finish  and  free  from  injurious  blowholes  and 
defects.  All  castings  must  be  annealed. 

When  tested  in  specimens  of  uniform  sectional  area  of  at 
least  -J  square  inch  for  a  distance  of  2  inches,  they  must 


27 

show  an  ultimate  strength  of  not  less  than  67,000  pounds 
per  square  inch,  an  elastic  limit  of  one-half  the  ultimate, 
and  an  elongation  in  2  inches  of  not  less  than  10  per  cent. 

The  metal  must  be  uniform  in  character,  free  from  hard 
or  soft  spots,  and  be  capable  of  being  properly  tool  finished. 

CAST  IRON. 

164.  Except  where  cast  steel  or  chilled  iron  is  required,  cast  iron. 
all  castings  must  be  of  tough,  gray  iron,  free  from  cold 
shuts  or  injurious   blowholes,  true  to  form  and  thickness, 

and  of  a  workmanlike  finish.  Sample  pieces,  i  inch  square, 
cast  from  the  same  heat  of  metal  in  sand  moulds,  shall  be 
capable  of  sustaining,  on  a  clear  span  of  12  inches,  a  central 
load  of  2,400  pounds,  when  tested  in  the  rough  bar.  A  blow 
from  a  hammer  shall  produce  an  indentation  on  a  rectangu- 
lar edge  of  the  casting  without  flaking  the  metal. 

TIMBER. 

165.  The  timber,  'unless   otherwise    specified,   shall    be  Timber. 
strictly  first-class  spruce,  white  pine,  southern  yellow  pine 

or  white  oak  bridge  timber,  sawed  true,  and  out  of  wind, 
full  size,  free  from  wind  shakes,  large  or  loose  knots* 
decayed  or  sap  wood,  worm  holes,  or  other  defects  impair- 
ing its  strength  or  durability.  It  will  be  subject  to  the 
inspection  and  acceptance  of  the  Engineer. 

INSPECTION. 

166.  All  facilities   for  inspection    of   the   materials  and  inspection 
workmanship   shall   be   furnished   by  the  contractor.     He 

shall  furnish  without  charge  such  specimens  (prepared)  of 
the  several  kinds  of  steel  to  be  used,  as  may  be  required  to 
determine  their  character. 

167.  The  contractor  must  furnish    the  use  of  a  testing 
machine  capable  of  testing  the  above  specimens  at  all  mills 
where  the  steel  may  be  manufactured,  free  of  cost. 

168.  Full  sized  parts  of   the  structure  may  be  tested  at 
the  option  of  the  Engineer,  but  if  tested  to   destruction, 
such  material  shall  be  paid  for  at  cost,  less  its  scrap  value 


28 

to  the  contractor,  if  it  proves  satisfactory.  If  it  does  not 
stand  the  specified  tests,  it  will  be  considered  rejected 
material,  and  be  solely  at  the  cost  of  the  contractor. 

PAINTING. 

Painting.  169.  All  metal  work  before  leaving  the  shop  shall  be  thor- 
oughly cleaned  from  all  loose  scale  and  rust,  and  be  given 
one  good  coating  of  pure  raw  linseed  oil,  well  worked  into 
all  joints  and  open  spaces. 

Buckle-plates  shall  be  given  a  thick  and  thorough  coat- 
ing of  red  lead  and  linseed  oil  before  shipment.  All  rivet 
heads  in  the  buckle-plate  floor  shall  also  be  coated  with 
this  read  lead  paint  as  soon  as  practicable  after  they  are 
driven. 

170.  In  riveted  work  the  surfaces  coming  in  contact  shall 
each  be  painted  before  being  riveted  together.     Bottoms  of 
bed- plates,   bearing- plates,   and   any  parts    which  are  not 
accessible  for  painting  after  erection,  shall  have  two  coats 
of  paint ;  the  paint  shall  be  a  good  quality  of  iron  ore  paint, 
mixed  with  pure  linseed  oil. 

171.  After  the  structure  is  erected,  the  metal  work  shall 
be  thoroughly  and  evenly  painted  with  two  additional  coats 
of  paint,  mixed  with  pure  linseed  oil.     All  recesses  which 
will  retain  water,  or  through  which  water  can  enter,  must 
be  filled  with  thick  paint  or  some  waterproof  cement  before 
receiving  the  final  painting. 

172.  Pins,  bored  pin-holes,  screw  threads  and  turned  fric- 
tion rollers  shall  be  coated  with  white  lead  and  tallow  before 
being  shipped  from  the  shop. 

ERECTION. 

Erection.  I73«  The  contractor,  unless  it  be  otherwise  specified,  shall 
furnish  all  staging  and  false  work,  shall  erect  and  adjust  all 
the  metal  work,  and  put  in  place  all  floor  timbers,  guards, 
etc.,  complete. 

174.  The  contractor  shall  so  conduct  all  his  operations  as 
not  to  interfere  with  the  work  of  other  contractors,  or  close 
any  thoroughfare  by  land  or  water,  except  by  written  con- 
sent of.... 


29 

175-  The  contractor  shall  assume  all  risks  of  accidents  to 
men  or  material  prior  to  the  acceptance  of  the  finished 
structure. 

The  contractor  must  also  remove  all  false  work,  piling 
and  other  obstructions,  or  unsightly  material  produced  by 
his  operations. 

FINAL  TEST. 

176.  Before  the  final  acceptance  the  Engineer  may  make  Final  Test, 
a  thorough  test  by  passing  over  each  structure  the  specified 
loads,  or  their  equivalent,  or  by  resting  the  maximum  load 
upon  the  structure  for  twelve  hours. 

After  such  tests  the  structures  must  return  to  their  orig- 
inal positions  without  showing  any  permanent  change  in 
any  of  their  parts. 

EXPORT  WORK. 

All  plans,  including  working  drawings,  must  be  submitted  Export  work, 
for  the  examination  and  approval  of  the  Consulting  Engineer 
before  the  material  is  ordered  or  any  work  done. 

Any  proposed  modification  of  accepted  plans,  to  adapt 
them  to  the  plant  and  methods  of  the  manufacturer  or  to 
facilitate  the  prompt  delivery  of  the  work,  must  also  be 
submitted  to  and  approved  by  the  Consulting  Engineer, 
before  such  changes  can  be  allowed. 

In  all  designs,  the  length  and  size  of  parts  must  be  so 
arranged  that  they  can  be  readily  handled  and  stored  dur- 
ing transportation  to  the  site. 

Length  of  bars,  posts,  chords  and  pieces  of  small  section 
must  not  exceed feet. 

Length  of  girders  or  girder  sections  over feet 

in  width  must  not  exceed feet. 

Weight  of  any  single  piece  must  not  exceed 

pounds. 

Pins,  roller-nests,  bolts,  rivets  and  all  small  pieces  must 
be  packed  in  strong,  iron-bound  boxes,  with  the  detailed 
contents  of  each  box  legibily  marked  on  the  outside.  Boxes 
to  be  consecutively  lettered  or  numbered. 


30 

The  screw-ends  of  all  bars  to  be  securely  protected  by 
canvass  wrapped  and  wired  about  the  same. 

Every  piece  must  not  only  be  legibily  marked  by  paint, 
but  also  by  letters  stamped  on  the  metal,  showing  its  loca- 
tion in  the  structure. 

All  necessary  rivets  for  the  field  connections,  with  an 
extra  allowance  of  25  per  cent,  for  each  kind,  shall  be  sent 
with  each  shipment. 

The  customary  pilot-nuts  (§  146)  for  all  pins  shall  be  sent 
with  the  pins. 


SUPPLEMENTARY. 

The  following  special  clauses  shall  apply  in  addition  to 
previous  general  clauses,  to  the  special  work  included  in 
the  attached  contract : 


31 
GENERAL  DATA. 

For  a  bridge  crossing- in  the  town 

of .County  of .State  of 

to  be  built  according  to  the  general 

requirements  of  the  accompanying  specifications: 

Width  of  roadway 

Number  of  foot  walks _. 

Width  of  footwalks 

Kind  of  floor  or  paving 

Number  of  car  tracks 

Spacing     "  "     _ 

Height  of  floor  above  flood  line 

Height  of  floor  above  ordinary  stage  of  water 

Depth  of  river  at  ordinary  stage  of  water.  _ 

Character  of  riverbed 

Usual  seasons  for  floods „ 

Length  of  haul  from  nearest  freight  station 

Specified  live  load,  Class  Ai,  A2,  B,  C,  D,  Ei  or  E2,  para- 
graph 38,  to  be  adopted  for  this  bridge 

Sizes  of  piers  (if  built  or  contracted  for) __ 

Skew  of  piers,  or  angle  of  current  with  line  of  the  bridge. 

Total  length  of  bridge __ 

Length  of  spans  centre  to  centre  of  piers 


APPENDIX. 


34: 


TABLE  I. 

MAXIMUM  END  SHEARS  S,  MOMENTS  M,  AND  REACTIONS  R  FOR  LIVE 
LOADS  (ONLY),  ON  STRINGERS  AND  FLOOR-BEAMS  OF  CLASS  Ex. 


Span. 

Each  stringer. 

FLOOR-BEAMS. 

Single  track. 

Double  track. 

L. 
Ft. 

& 

Lbs. 

M. 

1000 
inch-lbs. 

Least 
size. 

R. 
Lbs. 

M. 
Lbs.-ft. 

R. 
Lbs. 

M. 
Lbs.-ft. 

10.   . 

12  000 
13  100 
14  000 
14  800 
15400 
16  000 
16  500 
16  900 
17  300 
17  700 
18000 
18  300 
18500 
18800 
19  000 
19  200 
19400 
19  600 
19  700 
19  900 
20  000 

360 
396 
432 
468 
504 
540 
576 
612 
676 
743 
810 
878 
946 
1  014 
1  083 
1  152 
1  221 
1  291 
1  360 
1  430 
1  500 

12-in.  I. 

12  000 

ad 

II 

03 

20  000 

24  000 

2Q 
(M 

II 

(^ 

40  000 

11  . 

Q 
1 
tj, 

93  |e* 
II 

in 

^ 
1 
« 

CQ 
II 

* 

12  

13. 

14  

15.. 

15-in.  /. 

16.  .. 

17.  . 

18... 

19... 

20  

21... 

22. 

18-in.  /. 

23... 

24 

25... 

20-in.  I. 

26 

27.... 

28... 

29  

30  

Moment  for  stringers  equals 

M=  ~  up  to  17  feet. 


M  =  P 


21 


over  17  feet,  in  foot-pounds. 


S  =  end  shear  of  one  stringer. 
M—  maximum  moment. 
P  —  concentrated  load  on  one  wheel. 
I  =  span  in  feet. 

d  =  distance  in  feet,  center  to  center  of  trusses. 
e  =  distance  in  feet,  center  to  center  of  tracks. 
f  =  "  "  •'  i4  stringers. 


35 


TABLE  II. 

SAME  FOB  CLASS  E2. 


Span. 

Each  stringer. 

FLOOR-BEAMS. 

Single  track. 

Double  track. 

L. 
Ft. 

8. 

Lbs. 

M. 

1000 
incb-lbs. 

Least 
size. 

R. 
Lbs. 

M. 
Lbs.  ft. 

R. 
Lbs. 

M. 
Lbs.  ft. 

10. 

9  000 
9  800 
10  500 
11  100 
11  600 
12  000 
12400 
12  700 
13  000 
13  300 
13500 
13  700 
13  900 
14  100 
14  200 
14  400 
14  500 
14  700 
14  800 
14  900 
15000 

270 
297 
324 
351 
378 
405 
432 
459 
507 
557 
607 
658 
709 
761 
812 
864 
916 
968 
1  020 
1  073 
1  125 

10-in.  7. 

II 

1 
II 

II 

T 

05 
II 

11 

12 

12-in.  7. 

15-in.  7. 
18-in.  7. 

13.... 

14. 

15... 

16...  

17.  ... 

18.  ... 

19... 

20  

21.... 

22..:: 

23.... 

24  

25... 

26  

27... 

28  

20-in.  7. 

29.  .. 

36 


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"  The  most  perfect  system  of  rules  to  insure  success  must 
be  interpreted  upon  the  broad  grounds  of  professional  intelli- 
gence and  common  sense." 


GENERAL  SPECIFICATIONS 


FOR 


STEEL  RAILROAD  BRIDGES 

AND  VIADUCTS. 


NEW    AND     REVISED     EDITION, 

1  9  O-l 


By   THEODORE   COOPER, 

Consulting  Engineer. 


By  THEODORE  COOPER,  M,  Am,  Soc,  0,  E. 

Specifications  for  Steel  Railroad  Bridges,  1901,    .        .    $0   50 

"   previous  editions  25 

"               "           Highway  Bridges,  1901,    .        .  50 

"    previous  editions  25 

American    Railroad    Bridges    (reprint   from  Transac- 
tions of  American    Society    of    Civil    Engineers, 

July,  1889),  60  pages,  8vo,  cloth,      .                       .  2  00 


FOR  SALE  BY 

ENGINEERING  NEWS  PUBLISHING  COMPANY, 

22O  Broad  way,  New  York. 


Copyright  by  THEODORE  COOPER, 

Consulting  Engineer,  35  Broadway,  New  York. 


General  Specifications  for  Steel  Railroad 
Bridges  and  Viaducts,         ; 


SIXTH  EDITION. 
1901_ 

GENERAL   DESCRIPTION. 

1.  All  the  structures  shall  be  of  wrought  steel,  as  specified. 
{§§  128-141.)     Cast-iron  or   cast- steel  may  be  used  in  the 
machinery  of  movable  bridges  and  in  special  cases  for  bed- 
plates. 

2.  The   following  kinds   of   girders   shall  preferably  be  Kind  of  Girders. 
employed: 

Spans,  up  to     20   feet Rolled    beams,   or   longitudinal 

trough  floors. 

"    -    20  to     75      " Riveted  plate  girders. 

75    to  120      " Riveted  plate  or  lattice  girders. 

"      1 20   to  150      " Lattice  or  pin-connected  trusses. 

"     over       150      " Pin-connected  trusses. 

Generally    "  double  track   through  "  bridges   will   have 
but  two  trusses,  to  avoid  spreading  the  tracks  at  bridges. 

In  calculating  strains  the  length  of  span  shall  be  under- Length  of  Span, 
stood  to  be  the  distance  between  centres   of  end  pins  for 
trusses,  and  between  centres  of  bearing  plates  for  all  beams 
and  girders. 

3.  The  girders  shall  be  spaced,  with  reference  to  the 

of   the    bridge,   as   required    by  local   circumstances,   and 
•directed  by  the  Engineer  of  the  Railroad  Company.    (§  5.) 


Longitudinal  floor  girders  shall  in  no  case  be  less  than 
three  feet  and  three  inches  from  centre  line  of  tracks  for 
single  track  bridges,  or  one-half  standard  distance  centre 
to  centre  of  tracks  for  double  track  bridges.  (§6.) 
Head-room.  ^  por  aii  through  bridges  and  overhead  structures  there 
shall  be  a  clear  head-room  of  21  feet  above  the  base  of  the 
rails,  for  a  width  of  six  feet  over  each  track. 

ciear width.  cj.  In  all  through  bridges  the  clear  width  from  the  centre 
of  the  track  to  any  part  of  the  trusses  shall  not  be  less  than 
seven  (7)  feet  at  a  height  exceeding  one  foot  above  the  rails 
where  the  tracks  are  straight,  and  an  equivalent  clearance, 
where  the  tracks  are  curved. 

[The  additional  clearance  required  on  curves  for  passen- 
ger cars,  54  feet  c.  to  c.  of  trucks  and  75  feet  over  all,  will 
be  as  follows  : 

For  curvature,  0.8  D  inches  on  each  side ; 

1.6  D  inches  between  tracks, 
where  D  equals  degree  of  curve. 

For  elevation,  the  clearance  at  top  of  the  car  on  inside  of 
curve  must  be  increased  2^  inches  for  each  inch  of  track 
elevation  ] 

6.  The  standard  distance,  centre  to  centre  of  tracks  on 

straight  lines,  will  be feet  for R.  R. 

Trestle  Towers.  7.  Each  trestle  bent  shall,  as  a  general  rule,  b?  composed 
of  two  supporting  columns,  and  the  bents  united  in  pairs  to 
form  towers  ;  each  tower  thus  formed  of  four  columns  shall 
be  thoroughly  braced  in  both  directions,  and  have  struts 
between  the  feet  of  the  columns.  Transversely  the  columns 
shall  have  a  batter  of  not  less  than  one  horizontal  to  six 
vertical  for  single  track,  and  one  horizontal  to  eight  vertical 
for  double  track.  The  feet  of  the  columns  must  be  secured 
to  an  anchorage  capable  of  resisting  double  the  specified 
wind  forces.  (§§  25,  27.) 

8.  Each  tower  shall  have  sufficient  base,  longitudinally, 
to  be  stable  when  standing  alone,  without  other  support 
than  its  anchorage.  (§§  25,  27.) 

Trestle  spans.     9.  Tower  spans  for  high  trestles  shall  not  be  less  than  30 
feet. 


10.  Unless  otherwise  specified,  the  form  of  bridge  trusses  Form  ot 
may  be  selected   by  the  bidder ;  for  through  bridges,  the 

end  vertical  suspenders  and  two  panels  of  the  lower  chord, 
at  each  end,  will  be  made  rigid  members.  In  general,  all 
spans  shall  have  end  floor  beams  for  supporting  the 
stringers;  such  end  floor  beams  may  have  one  intermediate 
bearing  on  the  masonry.  In  through  bridges,  the  floor 
beams  shall  be  riveted  to  the  posts,  above  or  below  the 
pins. 

11.  All  lateral,  sway  and  portal  bracing  must  be  made  of  Lateral  Bracing, 
shapes  capable  of  resisting  compression  as  well  as  tension, 

and  must  have  riveted  connections. 

12.  The  wooden  floors  will  consist  of  transverse  ties  or  wooden  Floor, 
floor  timbers;  their  scantling  will  vary  in  accordance  with 

the  design  of  the  supporting  steel  floor.  (§  15.)  They  shall 
be  spaced  with  openings  not  exceeding  six  inches,  and  shall 
be  notched  down  y2  inch  and  be  secured 'to  the  supporting 
girders  by  f-inch  bolts  at  distances  not  over  six  feet  apart. 
For  deck  bridges  the  ties  will  extend  the  full  width  of  the 
bridge,  and  for  through  bridges  at  least  every  other  tie 
shall  extend  the  full  width  of  bridge  fora  footwalk. 

13.  There  shall  be  a  guard  timber  (scantling  not  less  than  Guard  Timbers. 
6x8")  on  each  side  of  each  track,  with  its  inner  face  parallel 

to  and  at feet inches  from  centre  of  track.    Guard 

timbers  must  be  notched  one  inch  over  every  floor  timber, 
and  be  spliced  over  a  floor  timber  with  a  half-and-half  joint 
of  six  inches  lap.  Each  guard  timber  shall  be  fastened  to 
every  third  floor  timber  and  at  each  splice  with  a  three- 
quarter  (|)  inch  bolt.  All  heads  or  nuts  on  upper  faces  of 
ties  or  guards  must  be  countersunk  below  the  surface  of 
the  wood.  (§  61.) 

14.  The  guard  and  floor  timbers  must  be  continuous  over 
all  piers  and  abutments. 

15.  The  maximum  strain  allowed  upon  the  extreme  fibre  Allowed  strain 
of  the  best  yellow  pine  or  white  oak  floor  timbers  will  be°n 

1,000  pounds  per  square  inch.  The  weight  of  a  single  en- 
gine wheel  may  be  assumed  as  distributed  over  three  ties, 
spaced  as  per  §  12. 


1 6.  The  floor  timbers  from  centre  to  each  end  of  span 
must  be  notched  down  over  the  longitudinal  girders  so  as 
to    reduce   the  camber  in  the   track,  as   directed   by  the 
Engineer. 

17.  All  the  floor  timbers  shall  have  a  full  and  even  bear- 
ing upon  the  stringers;  no  open   joints  or   shims   will  be 
allowed. 

1 8.  On  curves  the  outer  rail  must  be  elevated,  as  may  be 
directed  by  the  Engineer. 

Proposals.  iQ.  In  comparing  different  proposals,  the  relative  cost  to 
the  Railroad  Company  of  the  required  masonry  or  changes 
in  existing  work  will  be  taken  into  consideration. 

20.  Contractors  in  submitting  proposals  shall  furnish  com- 
plete strain  sheets,  general  plans  of  the  proposed  structures, 
and  such  detail  drawings  as  will  clearly  show  the  dimen- 
sions of  all  the  parts,  modes  of  construction   and  the  sec- 
tional areas. 

21.  Upon  the  acceptance  of  the  proposal  and  the  execu- 
tion of  contract,  all  working  drawings  required  by  the  En- 
gineer must  be  furnished  free  of  cost. 

Approval  of  22-  No  work  shall  be  commenced  or  materials  ordered 
until  the  working  drawings  are  approved  by  the  Engineer 
in  writing;  if  such  working  drawings  are  detained  more 
than  one  week  for  examination,  the  Contractor  will  be 
allowed  an  equivalent  extension  of  time. 

LOADS. 

23.  All  the  structures  shall  be  proportioned  to  carry  the 
following  loads: 

ist.  The  weight  of  metal  in  the  structure  and  floor. 
Dead  Load.  2d.  The  weight  of  rails,  fastenings,  ties,  guards,  footwalk 
and  ballast  when  used.  The  rails  and  fastenings  being 
assumed  at  100  pounds  per  foot  of  track ;  timber  at  4^ 
pounds  per  foot  B.  M. ;  and  ballast  at  no  pounds  per 
cubic  foot.  Minimum  will  be  assumed  at  400  pounds  per 
foot  of  track. 

These  two   items,  taken   together,    shall   constitute   the 
"  dead  load." 


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Live  Loads.  36.  A  "  live  load  "  on  each  track,  supposed  to  be  moving- 
in  either  direction,  consisting  of  two  "  consolidation  "  en- 
gines, coupled  and  followed  by  a  train  load,  distributed  as 
shown  on  diagram  E ;  or  a  special  load  equally  dis- 
tributed on  two  pairs  of  driving  wheels,  spaced  six  feet,  cen- 
tre to  centre,  of  100,000  pounds  up  to  class  £40 ;  and  of 
120,000  pounds  for  all  classes  above  £40. 

NOTE. — As  all  the  wheel  loads  in  each  diagram  are  made 
of  the  same  percentages  of  the  driving  wheel  loads,  the 
strains  due  to  the  different  engine  diagrams  will  be  pro- 
portionate to  the  numerical  classes  of  the  engines. 

Any  intermediate  numbers  may  be  selected,  with  the  un- 
derstanding that  this  rule  of  proportion  applies. 

The  maximum  strains  due  to  all  positions  of  either  of  the 
above  "  live  loads,"  of  the  required  class,  and  of  the  "  dead 
loads,"  shall  be  taken  to  proportion  all  the  parts  of  the 
structure. 

wind  Bracing.  24.  To  provide  for  wind  strains  and  vibrations  from 
high-speed  trains,  the  top  lateral  bracing  in  deck  bridges, 
and  the  bottom  lateral  bracing  in  through  bridges,  shall  be 
proportioned  to  resist  a  lateral  force  of  600  pounds  for  each 
foot  of  the  span  ;  450  pounds  of  this  to  be  treated  as  a  mov- 
ing load,  and  as  acting  on  a  train  of  cars,  at  a  line  6  feet 
above  base  of  rail. 

The  bottom  lateral  bracing  in  deck  bridges,  and  the  top 
lateral  bracing  in  through  bridges,  shall  be  proportioned  to 
resist  a  lateral  force  of  150  pounds  for  each  lineal  foot  for 
spans  up  to  300  feet,  and  10  pounds  additional  for  each 
additional  30  feet. 

25.  In  trestle  towers  the  bracing  and  columns  shall  be 
proportioned  to  resist  the  following  lateral  forces,  in 
addition  to  the  strains  from  dead  and  live  loads : 

ist.  With  either  one  track  loaded  with  cars  only,  or 
with  both  tracks  loaded  with  maximum  train  load,  the 
lateral  forces  specified  in  §  24 ;  and  a  lateral  force  of  100 
pounds  for  each  vertical  lineal  foot  of  the  trestle  bents  ;  or 

2d.  With  both  tracks  unloaded,  a  lateral  force  of  500 
pounds  for  each  longitudinal  lineal  foot  of  the  structure,  act- 


ing  at  the  centre  line  of  the  girders  ;  and  a  lateral  force  of 
200  pounds  for  each  vertical  lineal  foot  of  the  trestle  bents. 

26.  For  determining  the  requisite  anchorage  for  a  loaded 
structure,  the  train  shall  be  assumed  to  weigh  800  pounds 
per  lineal  foot. 

27.  The  strains  produced  in  the  bracing  of  the  trestle  Longitudinal 
towers,  in  any  members  of  the  trusses  or  in  the  attachments  F° 

of  the  girders  or  trusses  to  their  bearings,  by  the  greatest 
tractive  force  of  the  engines  or  by  suddenly  stopping  the 
maximum  trains  on  any  part  of  the  work  must  be  provided 
for;  the  coefficient  of  friction  of  the  wheels  on  the  rails 
being  assumed  as  0.20. 

28.  Variation  in  temperature,  to  the  extent  of  1 50  degrees,  Temperature, 
shall  be  provided  for. 

29.  When  the  structures  are  on  curves,  the  additional  £^ifugal 
effects  due  to  the  centrifugal  force  of  trains  shall  be  con- 
sidered as  a  live  load.     It  will  be  assumed  to  act  5  feet 
above  base  of  rail,  and  will  be  computed  for  a  speed  of 
60-30  miles  per  hour;  D  being  the  degree  of  curve. 

30.  All  parts  shall  be  so  designed  that  the  strains  coming 
upon  them  can  be  accurately  calculated. 

PROPORTION  OF   PARTS. 

31.  All  parts  of  the  structures  shall  be  proportioned  in  Tensile  strain. 
tension  by  the  following  allowed  unit  strains : 

For  Medium  Steel.  Pounds  per 

square  inch. 

Floor  beam  hangers,  and  other  similar  members 

liable  to  sudden  loading,  net  section...^ 6,000 

Longitudinal,  lateral  and  sway  bracing,  for  wind 

strains  (§§8,  24,  25) 18,000 

Longitudinal,  lateral  and  sway  bracings,  for  live 

load    Strains  (§§  27,  29,    105) _. __.  I2,OOO  Medium  Steel. 

Solid  rolled  beams,  used  as  cross  floor  beams  and 

stringers _ 10,000 

Bottom  flanges  of  riveted  cross  girders,  net  section.        10,000 

Bottom  flanges  of  riveted  longitudinal  plate  gird- 
ers, used  as  track  stringers,  net  section 10,000 

Bottom  chords,  main  diagonals,  counters   iive  loads.   dead°ioads. 
and  long  verticals 1 0,000      20,000 


'8 

For  swing  bridges  and  other  movable  structures,  the  dead 
load  unit  strains,  during  motion,  must  not  exceed  three- 
fourths  of  the  above  allowed  unit  strains  for  dead  load  on 
stationary  structures. 

The  areas  obtained  by  dividing  the  live  load  strains  by 
the  live  load  unit  strains  will  be  added  algebraically  to  the 
areas  obtained  by  dividing  the  dead  load  strains  by  the 
dead  load  unit  strains  to  determine  the  required  sectional 
area  of  any  member.  (§  47.) 

Soft  steei.     Soft  Steel  may  be  used  in  tension  with  unit  strains  ten 
per  cent,  less  than  those  allowed  for  Medium  Steel. 

32.  Angles  subject  to  direct  tension  must  be  connected 
by  both  legs,  or  the  section  of  one  leg  only  will  be  con- 
sidered as  effective. 

Net  section.  33.  In  members  subject  to  tensile  strains  full  allowance 
shall  be  made  for  reduction  of  section  by  rivet-holes,  screw- 
threads,  etc.  (§  60.) 

34.  Compression  members  shall  be  proportioned  by  the 
following  allowed  unit  strains  : 


Medium  Steel. 


For  Medium  Steel. 
Chord  segments  P=  10,000— 45— for  live  load  strains. 


P=2o,ooo — 90 — for  dead  load  strains. 


All     posts    of  i 

through      P==  8,500— 45  — for  live  load  strains, 
bridges. 

P=i7,ooo— 90_for  dead  load  strains. 


All     posts    of  / 

deck  bridges      />=  9,000— 40— for  live  load  strains. 


and  trestles. 


1 8,000—  80— for  dead  load  strains. 


9 
End  posts  are  not  to  be  considered  chord  segments. 

Lateral  struts  j 

and    rigid    P=  13,000 — 60— for  wind  strains; 
bracing. 

for  live  load  strains  use  two-thirds  of  the  above.   (§§  27,  29, 


P=the  allowed  strain  in  compression  per  square  inch  of 
cross-section,  in  pounds. 

/=the  length  of  compression  member,  in  inches,  c.  to  c., 
of  connections. 

r=the  least  radius  of  gyration  of  the  section,  in  inches. 

No  compression  member,  however,  shall  have  a  length 
exceeding  100  times  its  least  radius  of  gyration  for  main 
members,  or  120  times  for  laterals. 

Soft  Steel  may  be  used  in  compression  with  unit  strains  Soft  steel, 
fifteen  per  cent,  less  than  those  allowed  for  Medium  SteeL 

For  swing  bridges  and  other  movable  structures,  the 
dead  load  unit  strains  during  motion  must  not  exceed  f-  of 
the  above  allowed  unit  strains  for  dead  load  on  stationary 
structures. 

35.  For  long  span  bridges,  when  the  ratio  of  the  length 
and  width  of  span  is  such  that  it  makes  the  top  chords  act- 
ing as  a  whole,  a  longer  column  than  the  segments  of  the 
chord,  the   chord  will   be   proportioned   for   this  greater 
length. 

36.  All  members  and  their  connections  subject  to  alter- Alternate 
nate  strains  of  tension  and  compression  shall  be  propor- Strams' 
tioned  to  resist  each  kind  of  strain.     Both  of  the  strains 
shall,  however,  be  considered  as  increased  by  an  amount 
equal  to  T8F  of  the  least  of  the  two  strains,  for  determining 

the   sectional    areas   by   the    above-allowed   unit  strains. 
(§§3i,34.) 

37.  The  strains  in  the  truss   members  or  trestle  posts  Effect  of  wind 
from  the  assumed  wind  forces  need  not  be  considered  ex-s?r£n°.rd 
cept  as  follows : 

ist.  When  the  wind  strains  on  any  member  exceed  30 


10 

per  cent,  of  the  maximum  strains  due  to  the  dead  and  live 
loads  upon  the  same  member.  The  section  shall  then  be 
increased  until  the  total  strain  per  square  inch  will  not 
exceed  by  more  than  30  per  cent,  the  maximum  fixed  for 
dead  and  live  loads  only. 

2d;  When  the  wind  strain  alone  or  in  combination  with  a 
possible  temperature  strain,  can  neutralize  or  reverse  the 
strains  in  any  member. 

38.  The  rivets  in  all   members,  other  than   those  of  the 
floor  and  lateral  systems,  must  be  so  spaced  that  the  shear- 
ing strain  per  square  inch  shall  not  exceed  9,000  pounds ; 
nor  the  pressure  on  the  bearing  surface  (diameter  X  thick- 
ness of  the  piece)  of   the  rivet-hole  exceed  15,000  pounds 
per  square  inch. 

The  rivets  in  all  members  of  the  floor  system,  including 
all  hanger  connections,  must  be  so  spaced  that  the  shearing 
strains  and  bearing  pressures  shall  not  exceed  80  per  cent, 
of  the  above  limits. 

The  rivets  in  the  lateral  and  sway  bracing  will  be  allowed 
50  per  cent,  increase  upon  the  above  limits  for  lateral  forces 
as  per  §§  24,  25,  but  not  per  §§  27,  29. 

In  the  case  of  field  riveting  (and  for  bolts  as  per  §  61)  the 
above-allowed  shearing  strains  and  pressures  shall  be  re- 
duced one-third. 

Rivets  and  bolts  must  not  be  used  in  direct  tension. 

39.  Pins  shall  be  proportioned  so  that  the  shearing  strain 
shall  not  exceed  9,000  pounds  per   square  inch  ;   nor  the 
pressure  on  the  bearing  surface  of  any  member  (other  than 
forged  eye-bars,  see  §  85)  connected  to  the  pin  be  greater 
per  square  inch  than  15,000  pounds  ;  nor  the  bending  strain 
exceed  18,000  pounds,  when  the  applied  forces  are  consid- 
ered as  uniformly  distributed  over  the  middle  half  of  the 
bearing  of  each  member. 

Combined  4O.  When  any  member  is  subjected  to  the  action  of  both 
ins>  axial  and  bending  strains,  as  in  the  case  of  end  posts  of 
through  bridges  (§  37),  or  of  chords  carrying  distributed 
floor  loads,  it  must  be  proportioned  so  that  the  greatest 
fibre  strain  will  not  exceed  the  allowed  limits  of  tension  or 
compression  on  that  member. 


11 

If  the  fibre  strain  resulting  from  the  weight  only,  of  any 
member,  exceeds  ten  per  cent,  of  the  allowed  unit  strain  on 
such  member,  such  excess  must  be  considered  in  propor- 
tioning the  areas. 

41.  In  beams  and  plate  girders  the  compression  flanges  compression 
shall  be  made  of  same  gross  section  as  the  tension  flanges. 

42.  Riveted  longitudinal  girders  shall  have,  preferably,  a  Depth  of 
depth  not  less  than  ^  of  the  span. 

Rolled  beams  used  as  longitudinal  girders  shall  have, 
preferably,  a  depth  not  less  than  T^  of  the  span. 

43.  Plate  girders  shall  be  proportioned  upon  the  supposi-piate  Girders, 
tion  that  the  bending  or  chord  strains  are  resisted  entirely  et 

by  the  upper  and  lower  flanges,  and  that  the  shearing  or 
web  strains  are  resisted  entirely  by  the  web-plate;  no  part 
of  the  web-plate  shall  be  estimated  as  flange  area. 

The  distance  between  centres  of  gravity  of  the  flange 
areas  will  be  considered  as  the  effective  depth  of  all  girders. 

44.  The  webs  of  plate  girders  must  be  stiffened  at  inter- web  Plates, 
vals,  not  exceeding  the  depth  of  the  girders  or  a  maximum 

of  5  feet,  wherever  the  shearing  strain  per  square  inch  ex- 
ceeds the  strain  allowed  by  the  following  formula : 
Allowed  shearing  strain  =  10,000  —  75/7, 
where  H  =  ratio  of  depth  of  web  to  its  thickness  ;  but  no 
web-plates  shall    be  less  than  three-eighths  of  an  inch  in 
thickness. 

45.  All  stiffeners  must  be  capable  of  carrying  the  maxi- stiffeners. 
mum  vertical  shear  without  exceeding  the   allowed   unit 
strain. 

P=  10,000  —  45-. 
r 

Each  stiffener  must  connect  to  the  webs  by  enough  rivets 
to  transfer  the  maximum  shear  to  or  from  the  webs. 

46.  Rolled  beams  shall  be  proportioned  (§§  31,  41)  by  Roiled  Beams, 
their  moments  of  inertia. 

47.  The  areas  of  counters  shall  be  determined  by  taking  counters, 
the  difference  in  areas  due  to  the  live  and  dead  load  strains 
considered  separately  (§  31);  the  counters  in  any  one  panel 
must  have  a  combined  sectional  area  of  at  least  three  square 


12 

inches,  or  else  must  be  capable  of  carrying  all  the  counter 
live  load  in  that  panel.     (§  86.) 

48.  Counters  shall  be  provided  and  proportioned,  so  that 
a  future  increase  of  25  per  cent,  in  the  specified  live  load 
shall  not  in  any  case  increase  the  allowed  unit  strain  more 
than  25  per  cent. 

DETAILS  OF  CONSTRUCTION. 

Details.  49.  All  the  connections  and  details  of  the  several  parts  of 
the  structures  shall  be  of  such  strength  that,  upon  testing, 
rupture  will  occur  in  the  body  of  the  members  rather 
than  in  any  of  their  details  or  connections. 

50.  Preference  will  be  had  for  such  details  as  shall  be 
most  accessible  for  inspection,  cleaning  and  painting  ;  no 
closed  sections  will  be  allowed. 

Riveting.  51.  The  pitch  of  rivets  in  all  classes  of  work  shall  never 
exceed  6  inches,  or  sixteen  times  the  thinnest  outside  plate, 
nor  be  less  than  three  diameters  of  the  rivet. 

52.  The  rivets  used  shall  generally  be  £  and  f  inch  diam- 
eter. 

53.  The  distance  between  the  edge  of  any  piece  and  the 
centre  of  a  rivet-hole  must  never  be  less  than  ij  inches, 
except  for  bars  less  than  2\  inches  wide  ;  when  practicable 
it  shall  be  at  least  two  diameters  of  the  rivet. 

54.  For  punching,  the  diameter  of  the  die  shall  in  no  case 
exceed  the  diameter  of  the  punch  by  more  than  TA¥  of  an 
inch,   and  all   holes  must   be  clean  cuts  without   torn  or 
ragged  edges. 

55.  All   rivet   holes  must   be  so  accurately  spaced  and 
punched  that  when  the  several  parts  forming  one  member 
are  assembled  together,  a  rivet  -^  inch  less  in  diameter  than 
the  hole  can  generally  be  entered,  hot,  into  any  hole,  with- 
out reaming  or  straining  the  metal  by  "  drifts  ";  occasional 
variations  must  be  corrected  by  reaming. 

56.  The   rivets  when   driven   must  completely   fill   the 
holes.     The  rivebheads  must  be  round  and  of  a  uniform 
size  for  the  same  sized  rivets  throughout  the  work.     They 
must  be   full  and  neatly  made,  and  be  concentric  to  the 


13 

rivet-hole,  and  thoroughly  pinch  the  connected  pieces  to- 
gether. 

57.  Wherever  possible,  all  rivets  must  be  machine  driven. 
The  machines  must    be   capable  of   retaining  the  applied 
pressure  after  the  upsetting  is  completed.     No  hand-driven 
rivets  exceeding  J  inch  diameter  will  be  allowed. 

58.  Field  riveting  must   be  reduced    to  a    minimum  or 
entirely  avoided,  where  possible. 

59.  All  holes  for  field  rivets,  except  those  in  connections 
of  the  lateral  and  sway  systems,  shall  be  accurately  drilled 
or  reamed  to  an  iron  template  or  be  reamed  true  while  the 
parts  are  temporarily  connected  together. 

60.  The  effective  diameter  of  a  driven  rivet  will  be  as- Net  sections, 
sumed  the  same  as  its  diameter  before  driving.     In  deduct- 
ing the  rivet-holes  to  obtain  net  sections  in  tension  mem- 
bers, the  diameter  of  the  rivet-holes  will  be  assumed  as  -J 

inch  larger  than  the  undriven  rivets. 

The  rupture  of  a  riveted  tension  member  is  to  be  con- 
sidered as  equally  probable,  either  through  a  transverse 
line  of  rivet-holes  or  through  a  diagonal  line  of  rivet-holes, 
where  the  net  section  does  not  exceed  by  30  per  cent,  the 
net  section  along  the  transverse  line. 

The  number  of  rivet-holes  to  be  deducted  for  net  section 
will  be  determined  by  this  condition. 

61.  When  members  are  connected  by  bolts  the  holes  mustBolts< 
be  reamed  parallel  and  the  bolts   turned  to  a  driving  fit. 
All  bolts  must  be  of  neat  lengths,  and  shall  have  a  washer 
under  the  heads    and    nuts  where  in  contact  with  wood. 
Bolts  must  not  be  used  in  place  of  rivets,  except  by  special 
permission. 

62.  All  nuts  must  be  of  hexagonal  shape. 

63.  All  joints  in  riveted  tension   members  must  be  fully  splices. 
and  symmetrically  spliced. 

64.  Riveted  tension  members  shall  have  an  effective  sec- 
tion through  the  pin-holes  25  per  cent,  in  excess  of  the  net 
section  of  the    member,  and  back  of  the  pin  at   least   75 
per  cent,  of  the  net  section  through  the  pin-hole. 

65.  In  continuous  compression  members,  as  chords  and 


14 

trestle  posts,  the  abutting  joints  with  planed  faces  must  be 
placed  as  close  to  the  panel  points  as  is  practicable,  and  the 
joints  must  be  spliced  on  all  sides  with  at  least  two  rows  of 
closely  pitched  rivets  on  each  side  of  the  joint. 

Joints  in  long  posts  must  be  fully  spliced. 

Abutting  joints.  66.  In  compression  members,  abutting  joints  with  un- 
tooled  faces  must  be  fully  spliced,  as  no  reliance  will  be 
placed  on  such  abutting  joints.  The  abutting  ends  must, 
however,  be  dressed  straight  and  true,  so  there  will  be  no 
open  joints. 

.  5^  Xhe  webs  of  plate  girders  must  be  spliced  at  all  joints 
by  a  plate  on  each  side  of  the  web. 

.  68.  All  web-plates  must  have  stiffeners  over  bearing 
points  and  at  points  of  local  concentrated  loadings ;  such 
stiffeners  must  be  fitted  at  their  ends  to  the  flange  angles, 
at  the  bearing  points. 

69.  All  other  angles,  filling  and  splice  plates  on  the  webs 
of  girders  and  riveted  members  must  fit  at  their  ends  to 
the  flange  angles,  sufficiently  close  to  be  sealed,  when 
painted,  against  admission  of  water. 

Web  piates.  70.  Web-plates  of  all  girders  must  be  arranged  so  as  not 
to  project  beyond  the  faces  of  the  flange  angles,  nor  on  the 
top  be  more  than  -^  inch  below  the  face  of  these  angles,  at 
any  point. 

71.  Wherever  there  is  a  tendency  for  water  to  collect, 
the  spaces  must  be  filled  with  a  suitable  waterproof  material. 
Flange  Plates.  72.  In  girders  with  flange  plates,  at  least  one-half  of  the 
flange  section  shall  be  angles  or  else  the  largest  sized  angles 
must  be  used.  Flange  plates  must  extend  beyond  their 
theoretical  length,  two  rows  of  rivets  at  each  end. 

73.  In  lattice  girders  and  trusses  the  web  members  must 
be  double  and  connect  symmetrically  to  the  webs  of  the 
chords.  The  use  of  plates  or  flats,  alone,  for  tension  mem- 
bers mnst  be  avoided,  where  it  is  possible;  in  lattice 
trusses,  the  counters,  suspenders  and  two  panels  of  the 
lower  chord,  at  each  end,  must  be  latticed ;  all  other  ten- 
sion members  must  be  connected  by  batten  plates  or  latticed. 
(See  Arts.  90,  91  and  92.) 


it 

74.  The  compression  flanges  of  beams  and  girders  shall  be  compression 
stayed  against  ^transverse    crippling  when  their  length  is 

more  than  sixteen  times  their  width.'  *>•  - 

75.  The  unsupported  width  (distance  between  rivets)  of  width  of  Plates, 
plates  subject  to  compression  shall  not  exceed  thirty  times 

their  thickness  ;  except  cover  plates  of  top  chords  and  end 
posts,  which  will  preferably  be  limited  to  forty  times  their 
thickness  ;  where  a  greater  relative  width  is  used  in  chords 
and  end  posts,  however,  only  forty  times  the  thickness 
shall  be  considered  as  effective  section. 

76.  The  flange  plates  of   all  girders  must  be  limited  in 
width  so  as  not  to  extend  beyond  the  outer  lines  of  rivets 
connecting  them  with  the  angles,  more  than  five  inches  or 
more  than  eight  times  the  thickness  of  the  first  plate.   Where 
two  or  more  plates  are  used  on  the  flanges,  they  shall  either 
be  of  equal  thickness  or  shall  decrease  in  thickness  outward 
from  the  angles. 

77.  Where  the  floor  timbers  are  supported  at  their  ends 
on  the  flange  of  one  angle,  such  angle  must  have  two  rows 
of  rivets  in  its  vertical  leg,  spaced  not  over  4  inches  apart. 

78.  For  main  members  and  their  connections  no  material  Thickness  of 
shall  be  used  of  a  less  thickness  than  f  of  an  inch  ;  and  for 
laterals  and  their  connections,  no  material  less  than  T5F  of 

an  inch  in  thickness  ;  except  for  lining  or  filling  vacant 
spaces. 

79.  The  heads  of  eye-bars  shall  be  so  proportioned  and  Eye  Bars, 
made,  that  the  bars  will  preferably  break  in  the  body  of 

the  original  bar  rather  than  at  any  part  of  the  head  or  neck. 
The  form  of  the  head  and  the  mode  of  manufacture  shall  be 
subject  to  the  approval  of  the  Engineer  of  the  Railroad 
Company.  (Art.  141.) 

80.  The  bars  must  be  free  from  flaws  and  of  full  thick- 
ness in  the  necks.     They  shall  be  perfectly  straight  before 
boring.     The  holes  shall  be  in  the  centre  of  the  head,  and 
on  the  centre  line  of  the  bar. 

81.  The  bars  must  be  bored  to  lengths  not  varying  from 
the  calculated  lengths  more  than  ^  of  an  inch  for  each  25 
feet  of  total  length. 


16 

82.  Bars  which  are  to   be    placed   side    by  side  in  the 
structure  shall  be  bored  at  the  same  temperature  and  of 
such  equal  length  that  upon  being  piled  on  each  other  the 
pins  shall   pass  through   the   holes  at    both  ends  without 
driving. 

83.  The  lower  chord  shall  be  packed  as  narrow  as  possi- 
ble. 

Pins-  84.  The  pins  shall  be  turned  straight  and  smooth  ;  chord 
pins  shall  fit  the  pin-holes  within  ^  of  an  inch,  for  pins  less 
than  4^  inches  diameter  ;  for  pins  of  a  larger  diameter  the 
clearance  may  be  -f$  inch. 

85.  The  diameter  of  the  pin  shall  not  be  less  than  three- 
quarters  the  largest  dimension  of  any  eye-bar  attached  to  it. 
The  several  members  attaching  to  the  pin  shall  be  so 
packed  as  to  produce  the  least  bending  moment  upon  the 
pin,  and  all  vacant  spaces  must  be  filled  with  wrought  fill- 
ing rings. 

Upset  Ends.  86.  All  bars  with  screw  ends  shall  be  upset  at  the  ends, 
so  that  the  diameter  at  the  bottom  of  the  threads  shall  be 
Y1^  inch  larger  than  any  part  of  the  body  of  the  bar.  Where 
closed  sleeve  nuts  are  used  on  adjustable  members  the 
effective  length  of  thread  shall  be  legibly  stamped  at  the 
screw  ends  of  each  bar.  Adjustable  counters  to  be  avoided 
where  practicable. 

87.  All  threads  must  be  of  the  United  States  standard, 
except  at  the  ends  of  the  pins. 

Hangers.  88.  Floor  beam  hangers  when  permitted  shall  be  made 
without  adjustment  and  so  placed  that  they  can  be  readily 
examined  at  all  times.  (§  10.) 

89.  All  the  floor  beams  must  be  effectually  stayed  against 
end  motion  or  any  tendency  to  rotate  from  the  action  of  the 
lateral  system. 
Compression     QO.  Compression   members  shall  be  of  steel,  and  of  ap- 

Members. 


91.  The  pitch  of  rivets  at  the  ends  of  compression  mem- 
bers  shall  not  exceed  four  diameters  of   the  rivets   for  a 
length  equal  to  twice  the  width  of  the  member. 

92.  The  open  sides  of  all  compression  members  shall  be 


17 

stayed  by  batten  plates  at  the  ends  and  diagonal  lattice- 
work at  intermediate  points.  The  batten  plates  must  be 
placed  as  near  the  ends  as  practicable,  and  shall  have  a 
length  not  less  than  the  greatest  width  of  the  member  or  i£ 
times  its  least  width.  The  size  and  spacing  of  the  lattice 
bars  shall  be  duly  proportioned  to  the  size  of  the  member. 
They  must  not  be  less  in  width  than  2  inches  for  members 
9  inches  or  less  in  width,  nor  2\  inches  for  members  12  to  9 
inches  in  width,  nor  2^  inches  for  members  15  to  12  inches 
in  width.  Single  lattice  bars  shall  have  a  thickness  not  less 
than  ^  or  double  lattice  bars  connected  by  a  rivet  at  the 
intersection,  not  less  than  -fa  of  the  distance  between  the 
rivets  connecting  them  to  the  members.  They  shall  be  in- 
clined at  an  angle  not  less  than  60°  to  the  axis  of  the  mem- 
ber for  single  latticing,  nor  less  than  45°  for  double  lattic- 
ing with  riveted  intersections.  The  pitch  of  the  latticing 
must  not  exceed  the  width  of  the  channel  plus  nine  inches. 

93.  Where   necessary,  pin-holes  shall    be   reinforced  by 
plates,   some  of   which  must  be  of  the  full  width  of  the 
member,  so  the  allowed  pressure  on  the  pins  shall  not  be 
exceeded,  and  so  the  strains  shall  be  properly  distributed 
over  the  full  cross-section  of  the  members.    These  reinforc- 
ing plates  must  contain  enough  rivets  to  transfer  their  pro- 
portion of  the  bearing  pressure,  and  at  least  one  plate  on 
each  side  shall  extend  not  less  than  six  inches  beyond  the 
edge  of  the  batten  plates.     (§  92.) 

94.  Where  the  ends  of  compression  members  are  forked 
to  connect  to  the  pins,  the  aggregate  compressive  strength 
of  these  forked  ends  must  equal  the  compressive  strength 
of  the  body  of  the  members. 

95.  In   compression   chord   sections  and  end   posts,  the 
material  must  mostly  be  concentrated  at  the  sides,  in  the 
angles  and  vertical  webs.     Not  more  than  one  plate,  and 
this  not  exceeding  \  inch  in  thickness,  shall  be  used  as  a 
cover  plate,  except  when  necessary  to  resist  bending  strains, 
or  to  comply  with  §  75.     (§40.) 

96.  The  ends  of  all  square-ended  members  shall  be  planed 
smooth,  and  exactly  square  to  the  centre  line  of  strain. 


18 
Floor  Beams       o7.  The  ends  of  all  floor  beams  and   stringers  shall  be 

and  Stringers.         " 

faced  true  and  square,  and  to  correct  lengths.  Allowance 
must  be  made  in  the  thickness  of  the  end  angles  to  provide 
for  such  facing  without  reducing  the  required  effective 
strength  of  such  end  angles. 

98.  All  members  must  be  free  from  twists  or  bends.  Por- 
tions exposed  to  view  shall  be  neatly  finished. 
Pin-Hoies.  99.  Pin-holes  shall  be  bored  exactly  perpendicular  to  a 
vertical  plane  passing  through  the  centre  line  of  each  mem- 
ber, when  placed  in  a  position  similar  to  that  it  is  to  occupy 
in  the  finished  structure. 

ico.  The  several  pieces  forming  one  built  member  must 
fit  closely  together,  and  when  riveted  shall  be  free  from 
twists,  bends  or  open  joints. 

Transverse  loi.  All  through  bridges  shall  have  latticed  portals,  of 
Brtfin?  approved  design,  at  each  end  of  the  span,  connected  rigidly 
to  the  end  posts  and  top  chords.  They  shall  be  as  deep  as 
the  specified  head-room  will  allow,  and  provision  shall  be 
made  in  the  end  posts  for  the  bending  strains  from  wind 
pressure.  (§24.)  (§4.)  (§  11.) 

102.  When  the  height  of  the  trusses  exceeds  25  feet,  an 
approved  system  of  overhead   diagonal  bracings  shall  be 
attached  to  each  post  and  to  the  top  lateral  struts. 

103.  All  members  of  the  web,  lateral,  longitudinal  or  sway 
systems  must  be  securely  riveted  at  their  intersections  to 
prevent  sagging  and  rattling. 

104.  Pony  trusses  and  through  plate  or  lattice  girders 
shall  be  stayed  by  knee  braces  or  gusset  plates  attached  to 
the  top  chords  at  the  ends  and  at  intermediate  points,  and 
attached  below  to  the  cross  floor  beams  or  to  the  transverse 
struts. 

Deck  Bridges.  io5.  All  deck  girders  shall  have  transverse  braces  at  the 
ends.  All  deck  bridges  shall  have  transverse  bracing  at 
each  panel  point.  This  bracing  shall  be  proportioned  to 
resist  the  unequal  loading  of  the  trusses. 

106.  In  double-track  deck  bridges,  where  three  trusses 
are  used,  all  three  trusses  will  be  made  of  equal  strength  ; 
the  unequal  loading  being  distributed  through  the  trans- 


19 

verse  diagonal  bracing  as  a  live  load.  (For  the  purpose 
of  reducing  the  unequal  deflection  under  single-track  load- 
ings.) 

107.  All  bed-plates  must  be  of  such  dimensions  that  the  Bed  Plates, 
greatest  pressure  upon  the  pedestal  stone  shall  not  exceed 

250  pounds  per  square  inch. 

108.  All  bridges  over   80  feet   span   shall   have  hinged  Friction 
bolsters  on  both  ends,  and  at  one  end  nests  of  turned  fric- 
tion rollers  running  between  planed  surfaces.    These  rollers 
shall  not  be  less  than  2-J  inches  diameter  for  spans  100  feet 

or  less,  and  for  greater  spans  this  diameter  shall  be  increased 
in  proportion  of  i  inch  for  100  feet  additional. 

The  rollers  shall  be  so  proportioned  that  the  pressure 
per  lineal  inch  of  roller  shall  not  exceed  the  product  of  the 
diameter  in  inches  by  300  pounds  (3Ood.). 

The  rollers  must  be  of  machinery  steel  and  the  bearing 
plates  of  medium  steel. 

The  rollers  and  bearings  must  be  so  arranged  that  they 
can  be  readily  cleaned  and  so  that  they  will  not  hold  water. 

109.  Bridges  less  than  80  feet  span  shall  be  secured  at 
one  end  to  the  masonry,  and  the  other  end  shall  be  free  to 
move  longitudinally  upon  smooth  surfaces. 

1 10.  Where  two  spans  rest  upon  the  same  masonry,  a  con- 
tinuous plate,  not  less  than  f  inch  thick,  shall  extend  under 
the  two  adjacent  bearings,  or  the  two  bearings  must  be 
rigidly  tied  together. 

in.  Pedestals  shall  be  made  of  riveted  plates  and  angles.  Pedestals  and 
All  bearing  surfaces  of  the  base  plates  and  vertical  webs 
must  be  planed.  The  vertical  webs  must  be  secured  to  the 
base  by  angles  having  two  rows  of  rivets  in  the  vertical 
legs.  No  base  plate  or  web  connecting  angle  shall  be  less 
in  thickness  than  £  inch.  The  vertical  webs  shall  be  of 
sufficient  height  and  must  contain  material  and  rivets 
enough  to  practically  distribute  the  loads  over  the  bearings 
or  rollers. 

Where  the  size  of  the  pedestal  permits,  the  vertical  webs 
must  be  rigidly  connected  transversely. 

112.  All  the   bed-plates  and  bearings   under  fixed  and 


20 

movable  ends  must  be  fox-bolted  to  the  masonry  ;  for 
trusses,  these  bolts  must  not  be  less  than  i£  inches  diameter ; 
for  plate  and  other  girders,  not  less  than  J  inch  diameter. 
The  contractor  must  furnish  all  bolts,  drill  all  holes  and  set 
bolts  to  place  with  sulphur  or  Portland  cement. 

113.  While  the  expansion  ends  of  all  trusses  must  be  free 
to  move  longitudinally  under  changes  of  temperature,  they 
shall  be  anchored  against  lifting  or  moving  sideways, 
camter.  114.  All  bridges  shall  be  cambered  by  giving  the  panels 
of  the  top  chord  an  excess  of  length  in  the  proportion  of 
%  of  an  inch  to  every  ten  feet. 

Trestle  Towers.  115.  The  lower  struts  in  trestle  towers  must  be  capable 
of  resisting  the  strains  due  to  changes  of  temperature  or  of 
moving  the  tower  pedestals  under  the  effects  of  expansion 
or  contraction. 

For  high  or  massive  towers,  these  lower  struts  will  be 
securely  anchored  to  intermediate  masonry  piers,  or  the 
tower  pedestals  will  have  suitably  placed  friction  rollers, 
as  may  be  directed  by  the  Engineer. 

116.  All  joints  in  the  tower  columns  shall  be  fully  spliced 
for  all  possible  tension  strains,  and  to  hold  the  parts  firmly 
in  position.     (§  65.) 

117.  Tower  footings  and  bed-plates  must  be  planed  on 
all  bearing  surfaces ;  and  the  holes  for  anchor  bolts  slotted 
to  allow  for  the  proper  amount  of  movement.     (§  28.) 

workmanship.  iiS.  All  workmanship  shall  be  first-class  in  every  par- 
ticular. 

119.  All  eye-bars  must  be  made  of  medium  steel. 
Eye-Bars.      i2o.  Eye-bars,  all   forgings   and  any  pieces  which  have 
been  partially   heated    or  bent   cold    must   be  wholly  an- 
nealed.    Crimped  stiffeners  need  not  be  annealed. 

121.  No   reliance  will   be   placed   upon   the  welding  of 
steel. 

122.  No  sharp   or  unfilleted  angles  or   corners  will   be 
allowed  in  any  piece  of  metal. 

Medium  steel.  123.  Medium  steel  may  be  used  in  compression  in  chords, 
posts  and  pedestals  without  reaming  of  punched  holes,  for 
all  thicknesses  of  metal,  which  will  stand  the  drifting  test 


21 

(§  !35);  provided  all  sheared  edges  are  planed  off  to  a  depth 
of  J>  inch. 

In  all  other  cases  medium  steel  over  £  inch  thick  must 
have  all  sheared  edges  planed  off  to  a  depth  of  £  inch  and 
all  holes  drilled  or  reamed  to  a  diameter  £  inch  larger  than 
the  punched  holes,  so  as  to  remove  all  the  sheared  surface 
of  the  metal. 

124.  Soft  steel  need  not  be  reamed  if  it  satisfies  the  drift- 
ing test  (§§  135,  136). 

125.  All  parts  of  any  tension   or  compression  flange  or 
member,  must  be  of  the  same  kind  of  steel,  but  webs  of 
plate  girders  and  the  tension  members  of  all  girders,  plate 
or  lattice,  may  be  made  of  soft  steel  in  connection  with 
compression  members  of  medium  steel. 

126.  All  splices  must  be  of  the  same  kind  of  steel  as  the 
parts  to  be  joined. 

127.  Pilot  nuts  must  be  used  during  the  erection  to  pro- pnot  Nuts 
tect  the  threads  of  the  pins. 

QUALITY  OF  MATERIAL. 

STEEL. 

128.  All  steel  must  be  made  by  the  Open  Hearth  process. 
The  phosphorus  must  not  exceed  0.06  of  one  per  cent,  for 
steel  made  by  the  acid  method,  or  0.04  for  steel  by  the  basic 
method. 

129.  The  steel  must  be   uniform  in    character  for   each 
specified  kind.     The  finished   bars,  plates  and  shapes  must 
be  free  from  cracks  on  the  faces  or  corners,  and  have  a 
clean,  smooth  finish.     No  work  shall  be  put  upon  any  steel 
at  or  near  the  blue  temperature  or  between  that  of  boiling 
water  and  of  ignition  of  hard  wood  sawdust. 

130.  The  tensile  strength,  elastic  limit*  and  ductility  shall 
be  determined  by  samples  cut  from  the  finished  material 
after  rolling.     The  samples  to  be  at  least  12  inches  long, 

*  For  the  purpose  of  these  specifications,  the  Elastic  Limit  will  be  considered  the  least 
strain  producing  a  visible  permanent  elongation  in  a  length  of  8  inches,  as  shown  by  scribe 
marks  of  a  pair  of  finely  pointed  dividers. 

lithe  yield  point  or  drop  of  the  beam  can  be  calibrated  for  any  machine  and  its  speed  to 
represent  the  elastic  limit  within  5  per  cent.,  it  may  be  used  for  general  cases.  Test  reports 
must  state  by  which  method  the  elastic  limit  was  determined. 


and  to  have  a  uniform^  sectional  area  not  less  than;J  sqtfafe 
inch. 

131.  Material  which  is  to  be  used  without  annealing  or 
further  treatment  is  to  be  tested  in  the  condition  in  which 
it  comes  from  the  rolls.     When  material  is  to  be  annealed 
or  otherwise  treated  before  use,  the  specimen  representing 
such  material  is  to  be  similarly  treated  before  testing,  for 
tensile  strength. 

The  elongation  shall  be  measured  on  an  original  length  of 
8  inches.  Two  test  pieces  shall  be  taken  from  each  melt  or 
blow  of  finished  material,  one  for  tension  and  one  for  bend- 
ing. (Art.  147.) 

132.  All  samples  or  full-sized  pieces  must  show  uniform 
fine   grained  fractures  of  a  blue  steel-gray  color,  entirely 
free  from  fiery  lustre  or  a  blackish  cast. 

Medium  steel.  133.  Medium  Steel  shall  have  an  ultimate  strength,  when 
tested  in  samples  of  the  dimensions  above  stated,  of  60,000 
to  68,000  pounds  per  square  inch,  an  elastic  limit  of  not 
less  than  one-half  of  the  ultimate  strength,  and  a  minimum 
elongation  of  22  per  cent,  in  8  inches.  Steel  for  pins  may 
have  a  minimum  elongation  of  15  per  cent. 

134.  Before   or  after   heating   to  a   low  cherry  red  and 
cooling  in  water  at  82  degrees  Fah.,  this  steel  must  stand 
bending  to  a  curve  whose  inner  radius  is  one  and  a  half 
times  the  thickness  of  the  sample,  without  cracking. 

135.  For  all   medium  steel,  f  inch  or  less  in  thickness, 
rivet  holes  punched  as  in  ordinary  practice  (§§  52,  53,  54), 
must  stand   drifting  to  a  diameter  one-third  greater  than 
the  original  holes,  without  cracking  either  in  the  periphery 
of  the  holes  or  on  the  external  edges  of  the  piece,  whether 
they  be  sheared  or  rolled. 

soft  steei.  136.  Soft  Steel  shall  have  an  ultimate  strength,  on  same 
sized  samples,  of  54,000  to  62,000  pounds  per  square  inch, 
an  elastic  limit  not  less  than  one-half  the  ultimate  strength, 
and  a  minimum  elongation  of  25  per  cent,  in  8  inches. 

For  soft  steel  the  above  drifting  test  (§  135)  shall  apply  to 
all  material  to  be  riveted. 

137.  Before  or  after  heating  to  a  light  yellow  heat  and 


23 

quenching  in  cold  water,  this  steel  must  stand  bending  180 
degrees,  to  a  curve  whose  inner  radius  is  equal  to  the 
thickness  of  the  sample,  without  sign  of  fracture. 

138.  Rivet  Steel  shall  have  an  ultimate  strength  of  5o,oooRivetSteel 
to  58,000  pounds  per  square  inch,  an  elastic  limit  not  less 

than  one-half  the  ultimate  strength  and  an  elongation  of  26 
per  cent. 

139.  The  steel  for  rivets  must,  under  the  above  bending 
test  (137),  stand  closing  solidly  together  without  sign  of 
fracture. 

140.  Eye-bar  material,    i^   inches  and  less  in  thickness,  Eye  Bars, 
shall,  on  test  pieces  cut  from  finished  material,  fill  the  above 
requirements.  For  thicknesses  greater  than  i £  inches,  there 

will  be  allowed  a  reduction  in  the  percentage  of  elongation 
of  I  per  cent,  for  each  -J  of  an  inch  increase  of  thickness,  to 
a  minimum  of  20  per  cent.  (Art.  119.) 

141.  Full  sized  eye-bars  shall  show  not  less  than  10  per 
cent,  elongation  in  the  body  of  the  bar,  and  an  ultimate 
strength   not   less   than    56,000   pounds    per   square   inch. 
Should  a  bar  break  in  the  head,  but  develop  10  per  cent, 
elongation  and  the  ultimate  strength  specified,  it  shall  not 
be  cause  for  rejection,  provided  not  more  than  one-third  of 
the  total  number  of  bars  tested  break  in  the  head. 

142.  Pins   over   7   inches   in   diameter  shall  be  forged. 
Blooms  for  pins  shall  have  at  least  three  times  the  sectional 
area  of  the  finished  pins. 

143.  A  variation  of  cross-section  or  weight  in  the  finished 
members  of  2%  per  cent,  from   the  specified  size  may  be 
cause  for  rejection. 

STEEL  CASTINGS. 

144.  Steel  castings  will  be  used  for  drawbridge  wheels,  steei castings, 
track  segments  and  gearing.      (Art.  i.) 

They  must  be  true  to  form  and  dimensions,  of  a  work- 
manlike finish  and  free  from  injurious  blowholes  and 
defects.  All  castings  must  be  annealed. 

When  tested  in  specimens  of  uniform  sectional  area  of  at 
least  ^  square  inch  for  a  distance  of  2  inches,  they  must 


f  /^V 

I  OF  THF  \ 

f  UNIVERSITY  ) 

\  ^ 


24 

show  an  ultimate  strength  of  not  less  than  67,000  pounds 
per  square  inch,  an  elastic  limit  of  one-half  the  ultimate, 
and  an  elongation  in  2.  inches  of  not  less  than  10  per  cent. 

The  metal  must  be  uniform  in  character,  free  from  hard 
or  soft  spots,  and  be  capable  of  being  properly  tool  finished. 

CAST  IRON. 

cast  iron.  HS-  Except  where  cast  steel  or  chilled  iron  is  required, 
all  castings  must  be  of  tough,  gray  iron,  free  from  cold 
shuts  or  injurious  blowholes,  true  to  form  and  thickness, 
and  of  a  workmanlike  finish.  Sample  pieces,  i  inch  square, 
cast  from  the  same  heat  of  metal  in  sand  moulds,  shall  be 
capable  of  sustaining,  on  a  clear  span  of  12  inches,  a  central 
load  of  2,400  pounds,  when  tested  in  the  rough  bar.  A  blow 
from  a  hammer  shall  produce  an  indentation  on  a  rectangu- 
lar edge  of  the  casting  without  flaking  the  metal. 

TIMBER. 

Timber.  146.  The  timber,  unless  otherwise  specified,  shall  be 
strictly  first-class  southern  yellow  pine  or  white  oak  bridge 
timber,  sawed  true,  and  out  of  wind,  full  size,  free  from 
wind  shakes,  large  or  loose  knots,  decayed  or  sap  wood, 
worm  holes,  or  other  defects  impairing  its  strength  or  dur- 
ability. It  will  be  subject  to  the  inspection  and  acceptance 
of  the  Engineer. 

INSPECTION. 

inspection.  147.  All  facilities  for  inspection  of  the  materials  and 
workmanship  shall  be  furnished  by  the  contractor.  He 
shall  furnish  without  charge  such  specimens  (prepared)  of 
the  several  kinds  of  steel  to  be  used,  as  may  be  required  to 
determine  their  character. 

148.  The  contractor  must  furnish    the  use  of   a  testing 
machine  capable  of  testing  the  above  specimens  at  all  mills 
where  the  steel  may  be  manufactured,  free  of  cost. 

149.  Full  sized  parts  of   the  structure  may  be  tested  at 
the  option  of  the  Engineer  of  the  Railroad  Company,  but 
if  tested  to  destruction,  such  material  shall  be  paid  for  at 


25 

cost,  less  its  scrap  value  to  the  contractor,  if  it  proves  satis- 
factory. If  it  does  not  stand  the  specified  tests,  it  will  be 
considered  rejected  material,  and  be  solely  at  the  cost  of 
the  contractor. 

PAINTING. 

150.  All  metal  work  before  leaving  the  shop  shall  be  thor- Painting, 
oughly  cleaned  from  all  loose  scale  and  rust,  and  be  given 

one  good  coating  of  pure  raw  linseed  oil,  well  worked  into 
all  joints  and  open  spaces. 

151.  In  riveted  work  the  surfaces  coming  in  contact  shall 
each  be  painted  before  being  riveted  together.     Bottoms  of 
bed-plates,   bearing-plates,   and   any  parts    which  are  not 
accessible  for  painting  after  erection,  shall  have  two  coats 
of  paint ;  the  paint  shall  be  a  good  quality  of  iron  ore  paint, 
mixed  with  pure  linseed  oil,  unless  otherwise  directed.     It 
will  be  subject  to  approval  of  the  Engineer. 

152.  After  the  structure  is  erected,  the  metal  work  shall 
be  thoroughly  and  evenly  painted  with  two  additional  coats 
of  paint,  mixed  with  pure  linseed  oil.     All  recesses  which 
will  retain  water,  or  through  which  water  can  enter,  must 
be  filled  with  thick  paint  or  some  waterproof  cement  before 
receiving  the  final  painting. 

153.  Pins,  bored  pin-holes,  screw  threads  and  turned  fric- 
tion rollers  shall  be  coated  with  white  lead  and  tallow  before 
being  shipped  from  the  shop. 

ERECTION. 

154.  The  contractor,  unless  it  be  otherwise  specified,  shall  Erection, 
furnish  all  staging  and  false  work,  shall  erect  and  adjust  all 

the  metal  work,  and  put  in  place  all  floor  timbers,  guards, 
etc.,  complete,  ready  for  the  rails. 

155.  The  contractor  shall  so  conduct  all  his  operations  as 
not  to  impede  the  operations  of  the  road,  interfere  with  the 
work  of  other  contractors,  or  close  any  thoroughfare  by 
land  or  water. 

156.  The  contractor  shall  assume  all  risks  of  accidents  to 
men  or   material   prior  to  the  acceptance  of  the  finished 
structure  by  the  Railroad  Company. 


The  contractor  must  also  remove  all  false  work,  piling* 
and  other  obstructions,  or  unsightly  material  produced  by 
his  operations. 

FINAL  TEST. 

Final  Test.  i$f.  Before  the  final  acceptance  the  Engineer  may  make 
a  thorough  test  by  passing  over  each  structure  the  specified 
loads,  or  their  equivalent,  at  a  speed  not  exceeding  60  miles 
an  hour,  and  bringing  them  to  a  stop  at  any  point  by  means 
of  the  air  or  other  brakes,  or  by  resting  the  maximum  load 
upon  the  structure  for  twelve  hours. 

Alter  such  tests  the  structures  must  return  to  their  orig- 
inal positions  without  showing  any  permanent  change  in 
any  of  their  parts. 


EXPORT  WORK. 

Export  work.  All  plans,  including  working  drawings,  must  be  submitted 
for  the  examination  and  approval  of  the  Consulting  Engineer 
before  the  material  is  ordered  or  any  work  done. 

Any  proposed  modification  of  accepted  plans,  to  adapt 
them  to  the  plant  and  methods  of  the  manufacturer  or  to 
facilitate  the  prompt  delivery  of  the  work,  must  also  be 
submitted  to  and  approved  by  the  Consulting  Engineer, 
before  such  changes  can  be  allowed. 

In  all  designs,  the  length  and  size  of  parts  must  be  so 
arranged  that  they  can  be  readily  handled  and  stored  dur- 
ing transportation  to  the  site. 

Length  of  bars,  posts,  chords  and  pieces  of  small  section 
must  not  exceed feet. 

Length  of  girders  or  girder  sections  over feet 

in  width  must  not  exceed feet. 

Weight  of  any  single  piece  must  not  exceed 

pounds. 

Pins,  roller-nests,  bolts,  rivets  and  all  small  pieces  must 
be  packed  in  strong,  iron-bound  boxes,  with  the  detailed 
contents  of  each  box  legibily  marked  on  the  outside.  Boxes 
to  be  consecutively  lettered  or  numbered. 


27 

The  screw-ends  of  all  bars  to  be  securely  protected  by 
canvass  wrapped  and  wired  about  the  same. 

Every  piece  must  not  only  be  legibiiy  marked  by  paint, 
but  also  by  letters  stamped  on  the  metal,  showing  its  loca- 
tion in  the  structure. 

All  necessary  rivets  for  the  field  connections,  with  an 
extra  allowance  of  25  per  cent,  for  each  kind,  shall  be  sent 
with  each  shipment. 

The  customary  pilot- nuts  (§  127)  for  all  pins  shall  be  sent 
with  the  pins. 


Proposals  for  building  and  erecting  complete,  ready  for 

the .: ,  a  bridge  over 

near 

on  the Division, 

Railroad,  in  accordance  with 

the  attached  specifications  and  accompanying  profile,  will  be 

received  up  to The 

live  load  to  be  adopted  for  this  bridge  will  be  Class  E , 

paragraph  23. 


APPENDIX. 


30 


TABLE  I. 

MAXIMUM  MOMENTS  M,  END  SHEARS  S,  AND  FLOOR-BEAM   REACTIONS 
R,  PER  TRACK,  FOR  LOADING  E  40,  FOR  GIRDER  BRIDGES. 


Span 
L. 
Ft. 

Max.  mom. 
M. 
Ft.-lbs. 

Max.  end  shear 
8. 
Ft.-lbs. 

Max. 
floor  reac. 
R. 
Ft.-lbs. 

EQUIVALENT  UNIFORM  LOAD. 

M. 
Lbs. 

S. 
Lbs. 

R. 
Lbs. 

10.... 

112  500 
131  400 
160  000 
190000 
220  000 
250  000 
280000 
310  000 
340  000 
373  200 
412  500 
452  000 
491  400 
530  800 
570  400 
610000 
649  600 
689  200 
731  000 
775  800 
821  000 
865  700 
910  800 
955  600 
1  000  700  . 
1  046  000 
1  097000 
1  148  500 
1  200  000 
1  253  500 
1  311  000 
1  427000 
1  543  000 
1  659  000 
1  776  000 
1  902  000 
2  030  000 
2  162000 
2  304  000 
2  446  000 
2  599  000 
2  753  000 
2  911  000 
3  079  000 
3247  000 
3  415  000 
3  584  000 
3  758  000 
3  942  000 
4  129  000 
4  321  000 
4  513  000 
4  713  000 
4  919  000 
5  128000 
5  341  000 
5  552  000 
5  771  000 
5  988  000 
6  213  000 
6  440  000 
7  075  000 
7774  000 
8  490  000 
9228  000 
9  993  000 

60  000 
65  500 
70  000 
73  800 
77  200 
80  000 
85  000 
89  500 
93  400 
96  800 
100  000 
102  800 
105  500 
107  900 
110  800 
113  600 
116  100 
118  500 
120  800 
123  100 
126  100 
128  800 
131  500 

ias  900 

136  100 
138  400 
141  100 
143  800 
146  200 
148  600 
150  800 
156  200 
161  100 
165  600 
169  600 
.  174  200 
178  500 
182  400 
186  000 
190800 
195  200 
200  200 
205  200 
210  000 
215  600 
221  000 
226  700 
232  600 
238  100 
243  400 
248  400 
253  800 
259  000 
264  200 
269  400 
274  500 
279  600 
284  TOO 
289  600 
295  000 
300  000 
312  200 
324  000 
335  800 
347  400 
358  800 

80  000 
87  300 
93  300 
98  500 
104  300 
109  300 
113700 
117  600 
121  300 
125  800 
131  100 
136000 
140  300 
144  300 
148  000 
151  300 
155400 
160  100 
164  600 
168  700 
172  500 
176  900 
182  000 
186  700 
191  100 
195200 

9  000 
8  690 
8  890 
9  000 
8  980 
8  890 
8  750 
8  580 
8  400 
8270 
8  250 
8  200 
8  120 
8030 
7  920 
7  810 
7  690 
7  560 
7  460 
7  370 
7300 
7  210 
7  120 
.7  020 
6  920 
6  840 
6  770 
6  710 
6  650 
6  590 
6  560 
6  480 
6  370 
6  280 
6  170 
6  090 
6  010 
5  930 
5  880 
5  820 
5780 
5  730 
5  690 
5  660 
5  610 
5  58-0 
5540 
5  490 
5460 
5  430 
5  400 
5  370 
5  340 
5  320 
5  300 
5  280 
5  250 
5230 
5  200 
5  180 
5  150 
5  150 
5  140 
5  140 
5  180 
5  120 

12  000 
11  910 
11  670 
11  350 
11  030 
10670 
10  620 
10  530 
10  380 
10  190 
10  OOJ 
9  790 
9  590 
9  380 
9  230 
9  090 
8930 
8  780 
8  630 
8  490 
8  410 
8  310 
8  220 
8  110 
8  010 
7  910 
7  840 
7770 
7  700 
7  620 
7540 
7  460 
7  320 
7  200 
7  070 
6  970 
6  870 
6  760 
6  640 
6  580 
6  510 
6  460 
6  410 
6  360 
6  340 
6  310 
6  300 
6  290 
6  270 
6  240 
6  210 
6  190 
6  190 
6  150 
6  120 
6  100 
6  080 
6060 
6  030 
6  020 
6  000 
5  950 
5  890 
5  840 
5  790 
5  740 

8  000 
7  940 
7  770 
7  580 
7  450 
7  290 
7  110 
6  920 
6  740 
6  620 
6  560 
6480 
6  380 
6  270 
6  170 
6  050 
5  970 
5  930 
5  875 
5  820 
5  750 
5  710 
5  690 
5  660 
5  620 
5  570 

11  ... 

12  . 

13  
14 

15  

16 

17.... 

18.. 

19  

20.. 

21.. 

22  

23  . 

£4  

25.. 

26 

27.. 

28 

29.  .. 

30. 

31.. 

32.. 

33.... 

34.. 

35 

36  
37. 

38 

39  . 

40 

42  

44 



46..  .. 

Trestles 
30  and  60  feet 
spans, 
238,900. 

48 



50 

52.... 
54 



56... 

58 

40  and  60  feet 
spans, 

262,900 

60... 

62  
64 

66.. 

68 

70  

72 

74 



76.... 

78 

80  

82 

84..  . 

86 

.........'. 

88  

90  
92  . 

94  

96 

98 

100..  .  . 
105 

no  

115 

120.... 

125..  . 

NOTE — For  all  other  classes,  the  above  values  to  be  proportional  to  the  classes. 


31 


TABLE  II. 

MAXIMUM  MOMENTS  M.  AND  END  SHEARS  S.  PER  TRACK,  PRODUCED  BY 
SPECIAL  LOADS  ON  Two  AXLES,     2  23. 


1 

.a 

OQ 

100,000  LBS.  FOR  ALL  CLASSES  UP 
TO  E  40. 

3 

120,000  LBS.  FOR  ALL  CLASSES  OVER 
E40. 

| 

Max. 
mom., 
M. 
Ft.-lbs. 

Max. 
shears, 
S. 
Lbs. 

Equiv.  unif  . 
load. 

Max. 
mom., 
M. 
Lbs. 

Max. 
shear, 
& 
Lbs. 

Equiv.  unif. 
load. 

M. 
Lbs. 

& 

Lbs. 

M. 
Lbs. 

S. 
Lbs. 

10.... 

11.... 

12.... 
13.... 
14.... 
15.... 
16.... 
17.... 
18.... 
19.... 
30.... 
21.... 
22.... 
28.... 
24.... 
25.... 
26.... 
27.... 
28.... 
29.... 

125000 
145500 
168750 
192  300 

70000 
72700 
75000 
76900 
78600 

10000 
9620 
9370 
9100 

14000 
13220 
12500 
11830 
11220 

E40 
E35 

E30 

150000 
174600 
202500 

84000 
87250 
90000 
92300 

12000 
11550 
11250 

16800 
15850 
15000 
14200 

E50 
E45 
E41 

230760 
259300 
288000 
316800 

11000 
10600 
10250 
9900 

216100 
240000 
264000 
288250 
312500 
336850 
361  200 

8820 
8540 
8250 
7990 
7700 
7460 
7220 

94300 
96000 
97500 

13500 
12800 
12200 

80000 
81250 
82300 
83300 
84200 

10670 
10160 
9680 
9260 
8860 

345900 
375000 
404200 
433500 

98800 
100000 
101100 

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9260 
8960 
8660 

11600 
11100 
10600 

85000 
85700 
86350 
86950 
87500 
88000 
88600 
88900 

8500 
8160 
7850 
7560 
7300 
7040 
6810 
6585 

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102900 

10300 
9800 

385700 
410200 
434800 
459400 
484000 
508650 
533300 
558000 
582900 

7000 
6780 
6570 
6380 
6200 
6020 
5850 
5700 
5540 

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8140 

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RELATIVE  COST  OF  BRIDGES 

Built  Under  These  Specifications 

FOR    THE 

DIFFERENT  CLASSES  OF  LOADINGS. 


The  increased  cost  and  weight  of  metal  of  bridges  of  all 
kinds,  built  under  the  requirements  of  these  specifications, 
will  be  approximately  as  follows  : 

For  bridges  of  Class  £35  over  those  of  Class  E  30  will  be 


E5o          "  N        £45 


Recommendation. 

Table  III  gives  a  selection  of  heavy  passenger  and  freight 
engines  in  use  on  the  principal  railroads  of  the  United  States 
at  the  end  of  the  Nineteenth  century. 

As  far  as  the  effects  upon  the  bridges  are  concerned,  these 
engines  are  represented  by  the  typical  train  loadings  of  these 
specifications,  E  35  to  E  50. 

That  the  heavier  of  these  engines  is  close  to  the  possible 
maximum,  considering  the  limitations  of  the  permissible  cross 
section  of  existing  railroads  and  the  mechanical  details  of 
design  and  proportions,  is  not  improbable. 

That  the  economical  tendency  towards  heavier  and  heavier 
engines  will  in  the  near  future  reach  the  heavier  class  E  50 
upon  the  most  important  roads,  is  to  be  expected. 

The  cars  will  also  follow  the  same  tendency  for  many  kinds 
of  traffic,  as  experience  justifies  the  advance. 

There  are  now  in  use  self-dumping  coal  cars  of  a  nominal 
capacity  of  100,000  pounds,  which  have  on  four  axles  a  total 


34 

load  of  146,000  pounds  (10  per  cent,  increase  over  nominal 
capacity)  on  a  wheel  base,  for  two  adjacent  cars,  of  17  ft.  2  ins. 
These  cars  on  all  ordinary  bridges  produce  strains  equivalent 
to  those  of  E  33. 

In  view  of  these  facts  and  tendencies,  it  is  recommended 
that  train  loading  E  35  be  the  minimum  adopted  for  any  rail- 
road in  the  United  States  having  a  future. 

Taking  into  consideration  the  relative  costs  of  the  several 
classes,  as  shown  above,  many  railroads  will  find  it  best  to 
adopt  classes  as  high  as  E  40  or  E  50. 

One  important  system  has  already  adopted  Class  E  50  for 
all  renewals  on  its  main  line. 

THEODORE   COOPER. 


SPECIFICATIONS 

...FOB... 


Electric 

Bridges. 


1902. 
C.  S.  Davis. 


S^NERAl 


COPYRIGHTED,  1902, 
BY  C.  S.  DAVIS,  TOLEDO,  OHIO. 


TABLE  OF  CONTENTS. 


GENERAL    DESCRIPTION.  Paragraphs. 

CLASSES   ...............................  i 

L.  20  ...................................  2-    3 

L.  30  ................................  ...  4-    5 

L.  40  ...................................  6-    7 

Recommendation    ........................  8 

TYPE  ..........  .........................  9 

MATERIAL  ...............  .  .............  TO 

CLEARANCE    .....  ...................... 

Sing!e  Track  ............................  if 

Double  Track  ..........................  .  u 

Curves  .............  ,  ...................  13 

CURVATURE  ...........................  14 

END  BEAMS  ............................  15 

STRINGER  SPACING  ...................  16 

GIRDER  SPACING  ......................  17 

FLOOR  DECK  ...........................  18 

Rails    ..................................  ig 

Cross-Ties    .........  '  ....................  20 

Guard-Rails    ............................  2  £ 

PLANS    .................................  ?2 

Stress  Sheet  .....  .......  ................  23 

Working  Drawings  ......................  24 

Changes    ...............................  25 

Extras  .....................  26 


II 

PATENTS    27 

PROPOSAL  2* 

Price 29 

Time 3;J 

Delays .    ..  31 

Damage 3- 

LOADS 33 

DEAD  LOAD    34-  35 

LIVE  LOAD 36 

L.  20 37 

L.  30 .:•  3* 

L-  40 39 

WIND  LOADS ;|p  ||  I  40 

Fixed  Load /.  41 

Moving  Load    ...  -  42 

Additional  Section 43-   44 

Initial  Stress 45 

Lateral  Struts   ; . .  -*  40 

CENTRIFUGAL  FORCE 47 

Additional  Section .|S 

Speed 49 

LONGITUDINAL  STRESSES 50 

UNIT  STRESSES 51 

TENSION 5I 

COMPRESSION 5r 

SHEARING  Si 

BEARING SI 

BENDING SI 

ALTERNATE  STRESSES ST 

COMBINED  STRESSES  5I 

TURNTABLE  DETAILS 5f 

VALUES  OF  ©  AND 


VALUES  OF  $  AND 


in 

2 


SHEARING  AND  BEARING  VALUE  OF 

RIVETS 54 

DETAILS  OF  DESIGN. 
LIMITING  SIZES. 

Thickness   55 

Angles 56 

Bars 57 

Columns •   58~  59 

Flanges 60 

Pins 61 

END  BEARINGS. 

Lead    62 

Anchors    63 

Pin  Bearings  •. 64 

Sliding  Knds 65 

Roller  Ends 66-69 

Pier  Plate 70 

CAMBER. 

Trusses 71 

Plate  Girders  72 

Framing  Out : . .    73 

RIVETS 74 

NET  SECTION 75 

ROLLED  BEAMS  76 

BUILT  BEAMS 77 

Flanges    78-  79 

Web  Plate   80 

Effective  Depth  Si 

Flange  Splice 82 

Web  Splice 83 

Stiffeners    84-  87 


IV 

Fillers    .........  .  .......................  88-  8g 

Rivet  Spacing  ................  ...........  90-  91 

Bracing   .........................  .  .......  92~  93 

End  Finish  ...............  .  .............  94-  95 

Ends  Faced    ............................  06 

PIN-CONNECTED  BRIDGES. 

Compression  Members   ...................  97-  08 

Battens    ....................  .  .....  ....  99 

L/attice  ............................  ...  100 

Riveting    ...........................  ...  101 

Pin  Plates  ..........................    102-103 

Pin  Holes  ..........................  .  .  10$ 

Splices  ..............................  v  105 

Eyebars  ...............................  106 

S  iffened  Sections   .......................  107 

Adjustable   Members    ....................  ioS 

Stringers  ...............................  109 

Beams   ................................  no 

Bracing  .  .............................    t  m 

Top  .Struts  ____  .  ...................  ...  -  112 

Knees    .........  ....  ..................  1  1  ? 


Cross  Bracing 
Portals    .  . 
VIADUCTS  OR  TRESTLES. 


Portals    .  .  ....................  .......         i  T  ^ 


Bents  ................................  \  f  •'        IT 

Towers 


I2O 
Bearings   ...............................         I2r 

Anchorage    .............................  122-12^ 

Bracing  .........................  ....... 


SWING  BRIDGES. 

Floor  System  .  .  . . , 125 

Trusses   126 

Tunitable    . 127 

Disc  Center   128 

Roller  Center >  129 

Rim  Bearing 130-132 

Latches    135 

End  Lifts  134 

Rail  Lifts   135 

End  Signa's 136 

Machinery    137 

Cables    138 

Motors 139-140 

Material    141 

Tender's  House : 142 

SHOP  WORK. 

FIRST  CLASS   143 

STRAIGHTENING 144-145 

PUNCHING 146 

REAMING 147 

DRILLING 148 

RIVETING , 149 

FACING    150-151 

FITTING 153 

PLANING  153-155 

PIN  HOLES   156-158 

LATHE  WORK 159 

EYEBARS. 

Material    i6o 

Heads    !6i 

Annealing Io*2 


VI 

ADJUSTABLE  RODS. 

Loop  Eyes 

Upsetting    164 

Annealing 165 

PAINTING. 

Cleaning   166 

Before  Assembling 167 

Inaccessible  Parts  168 

Machined  Surfaces 16^ 

Other  Parts  170 

Application   171-174 

FIELD  WORK. 

READY  FOR  RAILS < ;;-...  175 

FLOOR  DECK  ^  176 

FALSEWORK  177 

INTERRUPTING  TRAFFIC  4  178 

RENEWAL 179 

ANCHORAGE , .'.  .  180 

WATCHMEN    i8t 

LAWS    182 

RISKS   ;  183 

REAMING   184 

RIVETING 185 

TURNED  BOLTS 186 

PILOT  NUTS  187 

PAINTING. 

Cleaning   , . .  jgS 

Rivet  Heads ig^ 

First  Coat    iV  193 

Second  Coat    !o  E 

Application 


VII 

QUALITY  OP  MATERIAL 
WROUGHT  STEEL. 

Process   193 

Finish    194 

Variation    195 

Phosphorus 196 

Test  Pieces 197-200 

Ultimate  Strength 201 

Elastic  Limit  202 

Elongation    203 

Reduction  of  Area  ' 204 

Fracture    205 

Bending 206 

Hard  Steel 207 

Medium  Steel   208 

Soft  and  Rivet  Steel 209 

Drifting 210 

Duplicate  Tests  211 

Marking   212 

Eyebar  Tests   213-218 

WROUGHT  IRON. 

Grade    219 

Test  Pieces 220 

Ultimate   Strength 221-222 

Elastic  Limit   22  ^ 

Elongation    224 

Bending    225-226 

CAST  STEEL. 

Process   227 

Phosphorus 22-3 

Coupon   22c; 

Annealing , 230 


VIII 

Blow  Holes   ->.  231 

Ultimate   Strength 232 

Elastic  Limit   •  •  233 

Elongation /,-:  234 

Reduction  of  Area 235 

CAST  IRON. 

Grade - •  •  ."  236 

Coupon   •  •  •  •  237 

Tests   ...v  238 

PHOSPHOR  BRONZE. 

Composition  239 

Coupon 240 

Tests 241 

BABBITT  METAL v .. .  2+2 

TIMBER .'.,-  243 

PAINT. 

Oil 244 

Red  Lead \ 245 

First  Field  Coat 246 

Second  Field  Coat 247 

INSPECTION. 

INSPECTOR  ,  24$ 

NOTICE  OF  ROLLING 249 

SURFACE  INSPECTION ./  250 

SUBSEQUENT     DISCOVERY     OF     DE- 
FECTS    251 

MARKS ', ,  ..:;  252 

FACILITIES 253 

FULL  SIZED  TESTS 254 

MAINTENANCE 255 

FIRST— PAINTING   256 

SECOND— INSPECTION 257 


SPECIFICATIONS 
FOR 

ILlectric  Railway  Bridges. 

By  C.  S.  DAVIS. 
1902. 

GENERAL  DESCRIPTION. 

(i)     Electric  railway  bridges  shall  be  classified  in  ac- 

— —  eordance  with  their  capacity  or  loading  they  will  be  called 

upon  to  carry.       In  these  specifications  there  will  be  three 

general  classes — L,  20,  L   30  and  L  40.     Intermediate  or 

heavier  classes  may  be  used  if  so  desired. 

L- 20-  (2)     Bridges  of     this  class  shall  be  designed  to 

carry  a  train  Of  electric  railway  passenger  cars,  and  also 
a  light  freight  or  express  service.  The  weight  of  the 
loaded  cars  should  not  exceed  80,000  pounds  each,  and 
the  length  of  each  car  should  not  be  less  than  40  feet. 

(3)  NOTE: — An  84-ton  locomotive  (engine  and 
tender)  may  be  used  during  construction  to  haul  sup- 
ply trains  at  slow  speeds,  or  a  56-ton  locomotive  may  be 
used  in  regular  service. 

L  3Q  (4)     Bridges  of  this  class   shall  be  designed  ?o 

carry  a  train  of  80,000  pounds  capacity  freight  cars 
hauled  by  an  electric  motor.  It  is  not  intended  to  in- 


L.40 


Recommendations. 


Type 


— 2 — 

elude  pressed  steel  cars  or  cars  less  than  40  feet  in 
length  in  this  ciass. 

(5)  NOTE; — A    1 27-ton   locomotive    (engine   and 
tender)  may  be  used  during  construction  to  haul  sup- 
ply trains  at  slow  speeds,  or  an  85-ton  locomotive  may 
be  used  in  regular  service. 

(6)  Bridges  of  this  class     shall     be  designed  to 
carry  a  train  of  100,000  pounds  capacity  freight  cars 
hauled  by  an  electric  motor.     It  is  intended  to  include 
pressed  steel  cars  and  other  cars  with  a  short  wheel 
base  in  this  class. 

(7)  NOTE — A    1 70- ton    locomotive    (enigne   and 
tender)  may  be  used  during  construction  to  haul  sup- 
ply trains  at  slow  speeds,  or  a  n 3-ton  locomotive  may 
be  used  in  regular  service. 


Material 


(8)  Although  loading  L  20  is  sufficient  for  the 
traffic  of  electric  railway  lines  at  the  present  time,  the 
Author,  in  view  of  the  rapid  development  of  the  service, 
recommends  a  loading  of  not  less  than  L  30.  See  tables 
of  equivalent  loads  in  the  appendix. 

(9)  The  type  of  bridge  used  wil'  depend  upon  local 
conditions,  but  the  following  wiil  be  preferred : 

Spans  of  20  feet  or  less — Rolled  beams. 
Spans  20  to  100  feet —      Plate  girders. 
Spans  100  to  120  feet —     Riveted  trusses. 
Spans  over  120  feet —        Pin-connected  trusses. 

(10)  All  timber  for  ties  and  guard-rails  shall  be  white 
oak.  All  metal  shall  generally  be  medium  steel,  but  soft  steel, 
wrought  iron,  cast  steel  and  cast  iron  may  be  used  as  noted 
hereafter. 


-3— 


Clearance 


Single  Track 


Double  Track 


Curves 


(n)  All  single 
track  through  bridges 
on  straight  track  shall 
have  a  clear  opening 
of  not  less  than  that 
shown  by  the  accom- 
panying diagram. 


Jv  T   \  Top  of  /?&/'/ 


Curvature 


End  Beams 


Stringer  spacing 


(12)  For  double  track  bridges,  the     clear  width 
shall  be  increased  by  an  amount  equal  to  the  distance 
between  centers  of  tracks. 

(13)  When  a  bridge     is  on  a  curve     additional 
c'earance  must  be  provided  so  that  the  net  clearance 
shall  not  be  less  than  given  above.     Curvature  of  track 
and  tip  of  car  due  to  super-elevation  of  outer  rail  must 
both  be  considered. 

(14)  When  a  bridge  is  located  on  a  curve  the  center 
line  of  the  bridge  must  be  parallel  to  the  chord  of  the  curve 
connecting  the  centers  of  the  track  at  the  ends  of  the  span, 
and  must  bisect  the  middle  ordinate  of  the  curve.    In  double 
track  bridges  the  center  between  tracks  shall  be  used  instead 
of  center  line  of  track  as  above. 

(15)  All  through  bridges  shall  have  end  beams  to 
carry  the  ends  of  stringers  over  piers  and  abutments. 

(16)  When  two  lines  of  stringers  are  used  for  each 


—4— 

track  they  shall  be  spaced  6  feet  6  inches  apart  center  to 
center.  When  four  lines  of  stringers  are  used  for  each 
track  the  distance  from  the  center  of  the  track  to  point  mid- 
way between  each  pair  of  stringers  shall  be  2  feet  6  inches, 
and  they  shall  be  so  spaced  that  the  bolt  fastening  the  guard- 
rail to  the  stringer  shall  pass  just  outside  the  flange  of  the 
outer  stringers. 

Girder  Spacing  (17)     Deck  girders,  less  than  80  feet  in  length  shall  be 

spaced  6  feet  6  inches  apart  center  to  center. 

Deck  girders  80  feet  or  more  in  length  shall  be  spaced 
8  feet  apart  center  to  center. 

Floor-deck  (18)     The  floor-deck,  consisting  of  rails,  guard-rails, 

cross-ties  and  the  fastenings  for  the  same,  shall  be  con- 
structed as  follows: 

Raik  (19)     The  rails  shall  be  what     are  known  as  T 

rails  and  shall  weigh  not  less  than  70  pounds  per  yard ; 
they  shall  be  spiked  to  each  cross-tie  with  two  spikes  to 
each  rail. 

Cross-ties  (20)     The  cross-ties,  of  white  oak,  shall  be  spaced 

at  intervals  of  not  more  than  16  inches  center  to  center, 
and  they  shall  not  be  less  than  7  inches  by  8  inches  by 
9  feet  for  stringers,  or  girders  spaced  6  feet  6  inches 
apart  and  8  inches  by  9  inches  by  n  feet  for  girders 
spaced  8  feet  apart.  They  shall  be  dapped  at  least  1-2 
of  an  inch  over  the  stringers,  but  must  not  be  dapped  to 
a  thickness  less  than  61-2  inches. 

Guardrails  (2I)     A  §"uard-rail,  of  white  oak,  shall  be  used 

along  the  outside  of  each  rail,  and  it  shall  be  notched 
I  inch  over  the  cross-ties  and  bolted  to  the  stringers 
through  every  third  tie  with  a  3-4  inch  round  bolt.  A 
cast  iron  washer  or  clip  shall  be  used  under  each  head, 


Plans. 


Sir  ess -sheets 


Working 

drawings 


Changes 


Extras 


— 5— 

and  a  cast  iron  washer  and  nut  lock  under  each  nut.  The 

distance  between  inner  faces  of  the  guard  rails  shall  be 

7   feet. 

(22)  The  Contractor  shall  prepare  stress-sheets  and 
working  drawings  upon  tracing  linen  which,  upon  comple- 
tion of  the  work  are  to  become  the  property  of  the  Railway 
Company. 

(23)  Before  beginning  work,  the  Contractor  shall 
submit  for  formal  approval  stress  sheets  of  a  uniform 
size,  18  by  24  inches,  showing: 

(a)  Length  of  span  center  to  center  of  end  bear- 
ings. 

(b)  Height  of  truss  between  centers  of  chords  or 
•   distance  back  to  back  of  flange  angles  for  stringers, 

beams  and  girders. 

(c)  Live  and  dead  loads  assumed  in  making  cal- 
culations. 

(d)  Stresses  in  all  members. 

(e)  Sections  and  cross-sectional  areas  of  all  mem- 
bers. 

(f)  Size  of  rivets  in  principal  members  and  re- 
quired rivet  spacing-  in  the  flanges  of  all  stringers,  floor 
beams  and  girders. 

(24)  Before  beginning  actual  construction  at  the 
bridge  shops  the  Contractor  shall  submit  for  formal 
approval  a  complete  set  of  working  drawings  of  a  unir 
form  size,  24  by  36  inches. 

(25)  After  the  approval  of  the  plans,  no  changes 
shall  be  made  without  the  written  consent  of  the  Rail- 
way Company. 

(26)  No  extra  charges,  due  to  changes  made,  shall 


Patents 


Proposal 


Price 


Time 


Delays 


Damage 


LOADS 


Dead  Load 


— 6— 

be  allowed  except  as  agreed  upon  in  writing  at  the  tinie 
the  changes  are  accepted. 

(27)  If  any  patented  devices  or  parts  are  used,  the 
Contractor  shall  protect  the  Railway  Company  against  all 
claims  on  account  of  such  patents. 

(28)  All   proposals   must  be   accompanied  by   stress- 
sheets  and  an  estimate  of  the  weight  of  each  span. 

(29)  The  price  named  in  the  proposal  shall  be  in 
Cents  per  pound  of  the  finished  weight  of  the  metal,  and 
shall  be  for  the  bridge  erected,  ready  for  the  rails.    The 
timber  guard-rails  and  cross-ties  will  be  furnished  de- 
livered at  the  bridge  site  by  the  Railway  Company  but 
shall  be  framed  and  put  in  place  by  the  Contractor. 

(30)  Each  Bidder  shall  state  in  his  proposal  a  time 
in  which  he  can  complete  the  bridge  after  the  acceptance 

"of  his  proposal,  and  the  Contractor  shall  agree  to  com- 
plete the  bridge  in  the  time  mentioned  in  his  proposal. 

(31)  When  delays  occur,  due  to  causes  beyond  the 
control  of  the  Contractor,  an  extension  of  time  will  be 
granted.    However,  notice  of  such  delay  must  be  given 
by  the  Contractor  at  the  time  of  its  occurrence. 

(32)  If  any  damage  is  caused  by  the  failure  of  the 
Contractor  to  complete  the  bridge  in  the  time  agreed 
upon  he  shall  be  liable  for  all  such  damage. 

(33)  All  bridges  shall  be  proportioned  to  carry  the  fol- 
lowing loads : 

(34)  A  dead  load  consisting  of  the  entire  weight  of  the 
structure.    The  weight  of  the  rails,  cross-ties,  guard-rails  and 
the  fastenings  for  the  same  shall  not  be  assumed  at  less  than 
30x3  pounds  per  foot  of  track. 

(35)  The  weight  of  the  floor  system  shall  be  considered 


as  applied  at  the  loaded  chord  and  the  remainder  of  the  dead 
load  as  applied  equally  between  the  loaded  and  unloaded 
chords  of  the  main  trusses. 

Live  Load  (36)  The  live  load  used  in  the  calculations  shall  be  one 

of  the  following  loadings : 

L  20  (37)  A  continuous,  uniformly  distributed  moving 

load  of  2000  pounds  per  foot  of  track,  and  a  concen- 
trated load  of  20,000  pounds  so  placed  as  to  produce 
the  maximum  effect  in  every  case. 

L  30  (38)  A  continuous,  uniformly  distributed  moving 

load  of  3,000  pounds  per  foot  of  track,  and  a  concen- 
trated load  of  30,000  pounds  so  placed  as  to  produce 
the  maximum  eflect  in  every  case. 

L  40  (39)  A.  continuous,  uniformly  distributed  moving 

load  of  4,000  pounds  per  foot  of  track  and  a  concen- 
trated load  of  40,000  pounds  so  placed  as  to  produce 
the  maximum  effect  in  every  case. 

Wind  I0**5  (40)  All  bridges  shall  be  braced  to  resist  the  fellow- 

ling  wind  loads : 

Fixed  Load  (41)  The  lateral  system  for  the  unloaded  chords 

of  a  bridge  shall  be  designed  for  a  fixed  wind  load  of 
150  pounds,  and  the  lateral  system  for  the  loaded  chords 
shall  be  designed  for  a  fixed  wind  load  of  200  pounds 
per  foot  of  bridge. 

Moving  Load  (42)  The  lateral  system  for  the  loaded  chords  of  a 

bridge  shall  be  designed  for  a  moving  wind  load  of 
300  pounds  per  foot  of  bridge  in  addition  to  the  fixed 
wind  load. 

Additional  (43)  When  the  stresses  from  wind  loads  in  the 

floor  beams  and  chords  of  the  main  trusses  exceed  one- 
third  of  the  stresses  from  live  and  dead  loads,  addition- 
al section  must  be  provided  for  such  excess 


q    __ 

(44)   When  the  top  flange  of  a  floor  beam  acts  a» 
a  strut  for  the  lateral  system,  additional  section  must 
be  provided  for  such  excess. 

-Initial  Stress  (45)   ^  adjustable  lateral  rods  shall  be  propor- 

tioned for  an  initial  stress  of  10,000  pounds  in  addition 
to  the  stresses  as  determined  above. 

Lateral  Struts  (4^)   Lateral  struts,  in  addition  to  the  wind  load 

stresses,  shall  be  considered  as  taking  the  resultant 
from  an  initial  stress  of  10,000  pounds  on  each  of  the 
adjustable  rods  attached  to  them. 

^Centrifugal  (47)   When  a  bridge  is  on  a  curve,  the  lateral  bracing 

shall  be  designed  to  resist  the  stresses  due  to  centrifugal 
force  in  addition  to  the  stresses  due  to  wind. 

Additional  (4^)   To  resist  the  stresses  from  centrifugal  force, 

-Section         .  additional  section  must  be  provided  in  the  floor  beams 

and  in  the  chords  of  the  main  trusses  to  resist  the  chord 

stresses  of  the  lateral  truss  due  to  the  centrifugal  force, 

(49)   Speed  for  the  moving  load  shall  be  assumed 

at  4O-2d  miles  per  hour  where  d  is  the  degree  of  cttrva* 

ture. 

(50)  Due  allowance  shall  be  made  for  the  stresses  due? 
Longitudinal 

Stresses  to  stopping  the  load  upon  the  bridge.     The  coefficient  ot 

friction  between  the  wheels  and  the  rails  shall  be  assumed 
at  0.20, 


UNIT  STRESSES 

(51)  All  members  shall  be  so  proportioned  that  the 
stresses  in  pounds  per  square  inch  will  not  exceed  those 
given  by  the  following  formula: 


10 


TFNSTON 

•     WROUGHT  IRON. 

SOFT  .STEEL. 

MEDIUM  STEEL. 

Main  members 

f     2     1 

{2     1 

f       2 

Counters  and 

8ooo(2-ej 

ft  r 

30  J2~e 

long  hangers 
Rolled  beam 

7000  jej 

—  i2_e| 

f       2     1 

flanges 
Built  beam 

8000  )  2-ej 

of       2      ) 

9000  J         ft  r 
90     *      2     ' 

f  2  I 

flanges 

8000  1  2-ej 

(.  ._!    2   ) 

f       2     ) 

Deam  Hangers 
Bracing 

OOOOS            £v  £ 

7000  (2  -ej 

f       2     1 

COMPRESSION 
Chords 

9OOO  "j 
(_2    -  O  ) 

iiooo[2_ej 

f                        H    f       2     1 

f               M  f    2 

Posts 

}*IL_]5'  K  j 

jy^      4«  r  I  2—  ef 
f*^     rM       2  } 

1               r    (2    e 

|                       1      |       2 

Literal  sfrirK 

f            4  '     ^^ 

j  Scxx)  —  35^  >  1  2  £ 
f                  hi2) 

{.taoi^   j2^ 

SHEARING 

V                               ^        V                   J 

4       f     2     * 

•j    IICKX)  —  5°    f  1           f)  ( 
2     ") 

5500/  2  1 

Web  plates 

Shon  rivet  « 

f22      1 

5OOO                    Q     > 

2     ) 

Field  rivets 

\2~Q\ 

6000  2-ej 

Pins 
BEARING 

V                          _/ 

i2    1 

5000  2_Q^ 

."      -i^e} 

Shop  rivets 

Ffofd  rtvpfe 

2-ej 
2  I 

12000  (a-e  J 
j    2  1 

Pins 

2-e{ 

^b-ej 

$       2      ) 

Rollers 

:  '                            f       2      ) 

Masonry 

f       2      ] 

f       2      | 

f2    2      \ 

BENDING 
Pins 

200  ('2-8  \ 

I5000|_^j 

ALTERNATE 
STRESSES 

Tension  and 
Compression 


COMBINED 
STRESSES 

Compression 

and  bending 
Tension  and 

bending 

TURNTABLE 
DETAILS 

Bearing: 
Bearing: 
Bearing: 
Bearing: 


—  II  — 
«4        in  place  of  i^f 


in  the  above  formulae 
and  proportion  for  both  compression  and  tension  and  use 
the  larger  area  obtained. 


A  -    f  V*  *? 


A  ~ 


NOTE 


r 

1 

f 

A 

C 

T 

M 

D 


Cast  iron  wheels  on  a  cast  iron  track 
Cast  steel  wheels  on  a  cast  steel  track 
Hard  steel  rollers  on  a  hard  steel  track 
Phosphor-bronze  discs  on  steel 


250  D!.^e 


400 

400 


2500  D   .J3_ 


Dead  load  stress  4-  Total  stress. 

Maximum  Stress  of  the  lesses  kind  -|-    Maximum  stress  of 

the  greater  kind. 
Distance  from  centre  of  inertia  to  outer  edge  of  the  section 

in  inches, 

Radius  of  gyration  in  inches, 
Length  of  member  in  inches. 
Unit  stress  from  above  formulae 
Required  cross  sectional  area. 
Total  direct  compression  in  pound*. 
Total  direct  tension  in  pounds. 
Bending  moment  in  inch  pounds. 
Diameter  in  inches. 

The  same  requited  areas  ivill  be  obtained  b\  diviaing 
the  live  load  stress  by  the  first  factor  of  the  above  formulae 
und  the  dead  load  Stress  by  two  times  the  same  factor  and 
adding  the  ftc'o  quot'ents  as  by  the  use  of  the  above  formulae. 


— 12 — 


(52)  Values  of  ®  and 


-e 


® 

'2 

® 

2 

2-e 

® 

2 

XH) 

2 

® 

2 

2-e 

2-e 

2—  e 

2-e 

j.ooo 
1.005 

|.OIO 

1-015 

!  .O2O 

i.oooo  .200 
1.0025  .205, 
1.0050  .210 

1.0076  .215 

I.OIOIJ.22O 

i.  mi 
^1.1142 
1.1173 
1.1205 
1.1236 

400 

•405 
.410 

•415 
.420 

1.2500!  60011.4286 
i.  2539  1.605!  i.  4337 
1.25791.610*1.4388 
i.  26181.615!  1.  4440 
i.2658f.62oji.4493 

.800^ 
.805 
.810" 

.815 
.820 

1.6667: 

1.6736^ 
"1.6807: 
1.6878 
1.6949; 

.025|l.OI27| 

.030!  i. 01 52] 

,.03511.01781 
1 .040 11.0204! 

1.045!  1.0230! 

1.050 1 1.0256! 
!.  05  5 11.0283! 
.060 1 1.0309!. 
i  -065 1 1. 0336 1 
1.07011.0363! 

1  075 1 1 -0390! 
i .080 1 1, 04.17 
1 .085 1 1. 0444! 
1.090  [1.047 1 1 
i-095 11 -°499 1 
1.100)1.0526! 
!. 1 05!  i. 0554] 
i.no!  1.0582! 
.ii5li.o6io| 
[.126(1.06381 

1.125  1-0667! 
1.130  1.0695! 


i.  140!  1.07531 
1.145!  1.07821 

1.  150!  i.  08111 


1.1651 1. 0899! 
!. 170!  1.0929! 


,  18011.0989 


.225 1 1. 1 267 1.425 1 1. 2698 1 
.230  1.1299  430^.2739 

.23511.1332  -435*1.2780 
.240!  1.13641.440!  1.2820! 
.245  j  1. 1 396(445 11.2862! 

.250 1 1. 1 429 1.450 1 1. 2903! 
.255|i.i46ii.455Ti.2945[ 
260  1.14941.46011.2987) 
.26511.15271.46511.3029! 
.270 1 1 . 1 561  j  47o[i  .3072 1 

.275]  1. 1594(4751 1.31 15! 
.280^1. 16281.480!  1.3158! 
.285^1 .1662  i  .485 1 1 .3201 
,29oj.i696f.49o[i.3245J 
•2951 1-1730 1 495!  ^3289 1 
.30011.17651.50011.3333! 
.305!  1.1799!  .505!  i.3378[ 
.310^1.18341.51011.3423! 
.31511.18691.51511.3468! 
.32011.19051.52011. 

.32511.19401.52511. 
.33011.19761.53011.3605! 
.335[i.2oi2l.  53511.3652! 

.34011.20481.54071.3699! 
.345!  1.20851.545!  1.3746! 

.35o|i.2i2i  .55o|i.3793i 

.355!  1.21581.55571.3841! 

.36ok.2i95l.56oi  1.3889! 
.36511.22321.56511.3937! 
.370^!  1.22701.570!  1.3986! 

•375ii. 2308!.  575 11.4035! 
.380!  i. 2346!. 580^1. 4085^ 


.625 1. i 
.630]  i 

•63?|i 
.640 1 1 
.645(1 

.650)1 

.655!  i 
.660  j  i 

-665!  i 


.675!  i 
.680!  i 
.685Ti 
.690!! 
•695 11 
.700!! 

.7io|i 
•7i5|i 


45451-825!  1.7021; 
4598 1.830  IT. 7094 
46521.83511.71671 
47061.8401.1.7241; 
4760'. 845!  i. 7316: 

4815^.85011.73911 

4925  (.86oT  i. 7544' 
49811.86511.7621! 
50381.87011.7699; 

,50941.875!  1.7778; 
.5i5il.88oTi.7857; 
.52097.88511.79371 
.52671.89011.8018; 
.53261.895^1.8100; 


1.190!  1.10501.390!  1.2422!. 590!  14184! 
Li95li.io8oj.395ii.246i  .595)  1.4235 1 


•73oi i 

•735!  i 
.740!  i 

•745 1 1 
•75oli 

•755! i 
.760!  i 

•765|i 
.770(1 

•775! i 
780(1 

•790!  i 
•795 1 1 

....|. 


.5504  .91071.83491 
.55641.91511.8433 
56251.92011.8519: 

.5686 1.92  5!  i.  8605 1 
.5748). 930!  1.8692! 
.58101.935!  1.8779' 
.58731.94071.8868: 
•59361 .9451*  .8957: 
.60001.95011.9048' 
.60641.95511.9139: 
.61291.96011  9231] 
.61947.965  Ti.  9324! 
.6260]  .970]  i. 941 7  i 

•6327l.975|i.95i2: 
•6393 1.980 11.9608; 
.64611.98511.9704: 
.65291.990^1.9802! 
•6597!-  995'i.  990 1 

|l.OOT2.OOOO 


•13— 


(53)  Values  of  <fc  and 


.000  1.  0000 

.005!  0.9975 

.010)0.9950 


.200)0.9091 
.20510.9070 
.2io|o.O95o 


1.80010.7143 


.405  [0.83 161.605)0.7678'. 

.410)  0.8299]. 61010.7663 1.81010.7118 


.01 5  (0.9926).  21 5  (0.9030).  41 5)0.8282!.  615  (0.7648).  815 10.7105 
.o2ojo.99Oi|.22o|o.9oo9.' .42010.8265]. 620)0. 7634). 82ojo. 7092 

.025(0,98771 
.03010.9852! 
.03510.9828] 
.0400.9804! 

.04510.9780! 

.05010.9756) 


.225  10.8989).  425  10.8248).  625  10.7620).  825^.7080 
0.8969).  43010.82311.630)0.7605!.  830(0.  7067 

0.89491.43510.82141.63510.7591  1.83510.7055 

0.8929!.  44o]o.8i97|.  64010.7576!.  84010.7042 
.245)0.8909).  445  jo.8i8o[.645  [0.7562;.  84510.7030 


.230 

.235 

.240 


_        25010.8889! 
0.97331.255(0.8869! 

0.9709]  .260 1 0.8850! 
265(0.8830 
270)0.8810) 


-055 
.060 

.065)0.9686] 
.07010.9662 


.450)0.8164!.  650)0.7548).  850(0.7018 
.455)0.8147!. 65510.7533!. 85510.7006 
.460)0.8130  .660 '0.7519! .860' 0.6993 

.465 10.8114).  665 10.7505).  865 1 0.698  r 
.470 1 0.8098 1 .670  ]  o.  749 1  .870 !  0.6969 


0.96391.275)10.87911.47510.80811.67510.7477 
0.96161.28010.87721.48010.80651.680)0.7463!. 


•075 
.080 

.085(0.95931.28510.87531.48510.8049!.  68510.7449).  88510.6933 


.090(0.9570!. 290)0.8734). 490(0.8033!. 690(0.7435  .89010.6921 
•095|o.9547|. 29510.8715!. 495|o.8oi6|. 695(0.7422  .89510.6909 

.100(0.95241 .300(0.8696]  .50010.8000)  .700)0.7408'  .900'  .06897 
.105  0.9502). 30510.8677). 505(0.7984]. 70510.7394!. 90510.6885 
.no  0.9480!. 3io|o.8658T.5io!o.7968|.7iolo. 7380!. 9io1o6S73 

0.9457! .  31510.86391.515)0.7952!.  71510.7367' •  9^5 '0.6862. 

0.9434!  .320(0.8621 1 .520(0.7937]  .720)0.7353!  .920)0.6850 


.120 

•125 
.130 


0.94121.32510.8602! 
0.939°! -330  0.8584! 

0.93681.235(0.8566! 
1400.93461.340(0.8548) 
145(0.93241.345(0.8529] 


525lo.792il 
53010.7905! 
53510.78901 


725lo.734o1 
730)0.7327! 
73510.7313! 


15010.93031 
155  0.9281) 
160 
165 


35010.85111 

355(0.84931 
0.92591.360(0.8475) 
0.92381.365(0.8457! 
170(0.92171.37010.84391 


175(0.9196] 
,18010.91751 

18510.9154! 
,190)0.9133! 


.37510.8421! 
.38010.8403! 
.385(0.8386! 

.390)0.8368! 

.195!  0,91 1 2  j.395 10.835  I  I 


545  10.7859] 

550)0.78431 
555  10.7828] 
560(0.78131 
565)0.77981 
57010.7782] 

57510.77671 
,58010.77521 
5850.7737 
59010.7722) 
o95io.77o8l 


92510.6838 
,93010.6826 
935)0.6814 
,94010.6803 
745  jo.7286( .  94510.6792 

750(0.7273). 95o!o.678o 
75510.72601.955:0.6769 
76oio.2747(  .96o'o.6757 
76510.72341.96510.6746 
77010.7221 


775  (0.7208 1.975 '0.6723 
780!  0.7 195 1.980' 0.67 1 2 
785  (0.7182!.  985  '0.670 1 
790 !  o.  7 1 69 '  .990 !  o  6690 
795io.7i56--795lo.6678 
!  r. 00(0.6667 


—  14— 


(54)     Shearing  and   Bearing  value  of  Rivets   in    pounds 
with  @  =  O. 


Diameter 


Iron  Rivets 


Shop    |    Field 


i  f  in.  Rivet. 
|  f  in.  Rivet. 
|  f  in.  Rivet. 
!  f  in.  Rivet. 
!  |  in.  Rivet. 
i  f  in.  Rivet. 


Single  Shear '  *534 

1562 
1953 
2344 
2734 
3068 


£  in.  Bearing 

5-16  in.  Bearing.  . 

-jf  in.  Bearing 

7-16  in.  Bearing.  . 
Double    Shear.  . 


1227 
1250 
1562 

1875 
2187 

2454 


Steel  Rivets 
Field 


Shop 


in.  Rivet.  |  Single    Shear |  2209  |  1767 


|  f  in.  Rivet. 
i  5  in.  Rivet. 
|  fin.  R?vet. 
i  f  in.  Rivet. 
J  in.  Rive'. 
!  |  in.  Rivet. 
|  f  in.  Rivet. 

!  f  in.  Rivet. 
|  }  in.  Rivet. 
|  |  in.  Rivet. 
I  fin.  Rivet. 
!  |  in.  Rivet. 
I  £  in.  Rivet. 
!  j  in.  Rivet. 
!  §  in.  Rivet. 
I  J  in.  Rivet. 
!  £  in.  Rivet. 


j:  in.  Bearing I  1875  1  1500  j 

5-16  in.  Bearing,   j  2344  |  1875  | 

f  in   Bearing |  2812  |  2250  I 

7-16  in.  Bearing.  .    3281  |  2625  i 

^  in.  Bearing 375°  I  3000  [ 

9-16  in.  Bearing.  .    4219  |  3375  | 
Double    Shear.  . .  .    4418  |  3534  | 


Single    Shear 

{  in.  Bearine 

5-16  in.  Bearing.  , 

:d  in.  Bearing 

7-16  in.  Bearing.  , 

^  in.  Bearing" 

Q-i6  in.  Bearing.  , 
15  in.  Bearing. 
!  TT-i6  in.  Bearing 
I  Double    Shear.  . 


1841   !  1534  ; 

1875  !  1562  i 
2344 !  1953 ! 

2812  !  2344  ! 

3281 !  2734 ; 
3682 !  3068  i 

2651 1  2209  i 
2250  i  1875 
2812  i  2344 1 

3375  I  2812  i 
3937  i  3281  I 

4500 !  375o  I 
5062  !  4219  • 

5302 !  4418 ; 


3006  | 
2187! 

2734  1 
3281  ! 
3828  I 

43751 
4922  I 
5469  I 
6015  ! 
6012  ! 


24051 
1750 1 
2187! 
2625 1 
3062 ! 
3500 ! 
3937  I 
4^75  ' 
48i2| 
4810  I 


3608  ! 
2625  ! 
32Si  ! 
3937  I 
4593  ! 
5250  I 
5906  ! 
6562  ! 
7218  ! 
7216! 


3006 1 
2187 ! 
2734 1 

3281  ! 
3828! 

4375  f 
4922 ! 
5469  i 
6015! 
6012  f 


DETAILS  OF 
DESIGN 

Limiting  Sizes 
Thickness 


Angles 


Bars 


Columns 


Flanges 

Fins 

End  Bearings 
Lead 

Anchors 


Pin  Bearings 


(55)  No  metal   less   than    5-i6   of   an   inch   thick- 
shall  be  used  except  for  fillers.  Web  plates  in  stringers 
beams  and  girders  shall  not  be  less  than  3-8  of  an  inch 
thick. 

(56)  No  angle  weighing  less  than   5  pounds  per 
lineal  foot  shall  be  used. 

(57)  No  bar  having  an  area  of  less  than  I  square 
inch  shall  be  used. 

(58)  The  ratio  of  the  length  of  any  column  to  its 
least  radius  of  gyration  shall  not  exceed  125  for  main 
members  and  150  for  lateral  struts. 

(59)  The  thickness  of  plates  in  columns  s'hall  not 
be  less  than  1-40  of  the  distance  between  supports  in 
a  direction  at  right  angles  to  the  line  of  stress  and  not 
less  than  1-16  of  the  distance  between  supports  or  rivets 
in  the  line  of  stress. 

(60)  Beams  and  girders  having  a  length  greater 
than  1 6  times  the  width  of  the  flange  shall  be  braced 
horizontally. 

(61)  The  diameter  of  no  pin  shall  be  less  than  3-4 
of  the  width  of  the  widest  bar  attached  to  the  same. 

(62)  Sheet  lead  not  less  than   1-8  of  an  inch  in 
thickness,  shall  be  interposed  between  a1!  bearing  plates 
and  masonry. 

(63)  All  bearings   shall  be  thoroughly   and   efB- 
cient-y  anchored  to  the  masonry  by  means  of  bolts,  not 
less  than  I   1-4  inches  in  diameter,  set  at  least  12  inches 
into  the  masonry  with  neat  Portland  cement  mortar. 

(64)  To  insure  a  more  even  bearing  on  the  ma- 
sonry, spans  of  80  feet  or  more  in  length  shall  have  pin 
end  bearings.    Cast  steel  pedestals  will  be  preferred  for 
plate  girder  spans. 


Sliding:  Ends 


Roller  Ends 


Pin  Plate 

Camber 
Trusses 


— 16— 

(65)  Spans  less  than  75  feet  in  length  may  have 
sliding  plates  at  one  end  of  the  span  to  allow  for  ex- 
pansion and  contraction  due  to  a  change  in  temperature 
of  150  degrees  Fahrenheit.     Each  bearing  shall  consist 
of  two  plates,  an  upper  or  shoe  plate  and  a  lower  or  ma 
sonry  plate.     Both  shoe  and  masonry  plates  shall  be 
planed,  and  the  joint  between  the  two  plates  shall  be 
planed    with    tongue   and   groove    for   both    fixed   and 
sliding  ends  of  the  span.    The  finished  thickness  of  the 
plates  shall'  not  be  less  than  3-4  of  an  inch.    The  anchor 
bolt  holes  in  the  shoe  plates  on  the  sliding  end  must  be 
slotted  to  allow   for  expansion   and   contraction. 

(66)  One  end  of  all  spans  of  75  feet  or  more  in 
length  shall  have  roller  end  bearings  to  permit  free  ex- 
pansion and  contraction,  due  to  a  change  in  temperature 
of  150  degrees  Fahrenheit. 

(67)  The  rollers  shall  not  be  less  than  3  inches  in 
diameter,  shall  be  turned  with  a  groove  at  the  center, 
and  shall  travel  between  shoe  and  masonry  plates,  each 
of  which  shall  be  planed  with  a  tongue. 

(68)  All  rollers  gf  a  single  bearing  shall  be  joined 
by  spacing  bars  at  their  ends.     All  roller  bearings  shall 
have  guards  to  protect   them   from   dirt   and   shall  be 
made  accessible  for  cleaning. 

(69)  For  heavy  or  long  spans,  segmental  rollers 
and  a  masonry  plate,  built  up  of  railroad  rails,  and  a 
plate  will  be  preferred. 

(70)  On   piers,   the   masonry  plate   shall  be  con- 
tinuous, extending  under  both  bearings  of  contiguous 
spans. 

(71)  All  trusses  shall  have  just  sufficient  camber 
so  that  under  a  full  load  the  truss  will  come  to  a  level 


Plate  Girders 


Framing  Out 


Rivets 


Net  Section 


Rolled  Beams 


Built  Beams 


Flanges 


-17- 
line.    This  will  be  accomplished  by  shortening  each  ten- 
sion member  and  lengthening  each  compression  mem- 
ber by  an  amount  equal  to  the  change  in  length  of  that 
member  under  full  load. 

(72)  Plate  girders  shall  be  given  a  camber  equal 
to  one  one-thousandth  of  the  span. 

(73)  One-half  of  the  camber  shall  be  framed  out 
in  the  beams  and  stringers,  and  the     ther  half  in  the 
ties. 

(74)  Rivets  shall  generally  be  3-4  and  7-8  of  an  inch 
in  diameter,  they  shall  be  spaced  at  least  3  diameters  apart 
and  except  in  lacing  bars  their  centers  shall  not  be  nearer 
the  edge  of  any  member  through  which  they  pass  than  I 
1-4  inches.    No  rivet  shall  have  a  grip  exceeding  five  times, 
its  diameter. 

(75)  The  net  section  of  any  tension  member  or  flange 
&hall  be  determined  by  a  plane  cutting  the  member  square 
across  at  any  point.     The  greatest  number  of  rivet  holes 
which  can  be  cut  by  the  plane  or  whose  centers  come  within 
cnc  inch  of  the  plane,  is  the  number  to  be  deducted  from 
the  gross  sectio  . 

(76)  Rolled  Beams  shall  be  proportioned  for  bending- 
stresses  in  accordance  with  their  moments  of  inertia. 

(77)  Built  beams,  used  for  stringers,  floor  beams  or 
girders,  shall  be  proportioned  in  accordance  with  the  fol- 
lowing assumptions : 

(78)  It  shall  be  assumed  that  the  bending  stresses 
are  resisted  entirely  by  the  flange  section.    No  part  of 
the  web  plate  shall  be  assumed  as  effective  for  flange 
section. 

(79)  Flanges    shall    be    proportioned    from    the 


Web  Plate 


Effective  Depth 


Flange  Splices 


Web  Splices 


Stiff  eners 


tension  stresses,  and  the  compression  flange  shall  have 
the  same  gross  section  as  the  tension  flange. 

(80)  It  shall  be  assumed  that  all  the  shear  is  car* 
ried  by  the  web  plate. 

(81)  The  effective  depth  shall  be  the  distance  be- 
tween centers  of  gravity  of  the  flanges  except  when  thi.-» 
exceeds  the  distance  out  to  out  of  flange  angles.     In  no 
case  shall  the  effective  depth  be  taken  at  more  than  the 
distance  out  to  out  of  flange  angles. 

(82)  So  far  as  possible,  splices  in  the  flanges  shall 
be  avoided.     When  splices  become  necessary,  all  joints 
must  be  fully  spliced,   all   abutting  surfaces   must  be 
machine  finished  and'  must  be  brought  into  perfect  con- 
tact in  assembling.     In  the  tension  flanges,  sufficient 
section  must  be  provided  in  the  splices  to  make  up  for 
all  lost  section  in  the  member  spliced. 

(83)  Splices  in  web  plates  shall  be  made  at  points 
where  stiffeners  occur,  and  shall  be  made  with  a  plate 
on  each  side  of  the  web,  wide  enough  to  take  two  rows 
of  rivets  on  each  side  of  the  sp'ice.     The  splice  plates 
shall  not  be  thinner  than  the  web  itself. 

(84)  When  the  unit  shear  on  the  web  plate  ex- 
ceeds that  allowed  by  the  formula 


stiffeners  sha'.l  be  used. 

NOTE:  —  S  =  Allowed  shear  in  pounds  per  square 


inch. 


h  =  Unsupported  height  of  web  in  inches, 
t  =  Thickness  of  web  in  inches. 
See  curves  in  appendix. 


Fillers 


Rivet  Spacing: 


—  19— 

(85)  Stiffeners  shall  consist  of  a  pair  of  angles, 
one  on  each  side  of  the  web  and  they  shall  be  spaced 
at  intervals,  about  equal  to  the  depth  of  the  girder. 

(86)  The  size  of  the  stiff ener  angles  shall  be  as 
follows,   depending  upon  the  width  of  the  horizontal 
'eg  of  flange  angles : 

For  an  8  inch  leg  use  6x3  1-2  x  3-8  angles. 
For  an  7  inch  leg  use  6  x  3  1-2  x  3-8  angless. 
For  a  6  inch  leg  use  5x3  1-2  x  3-8  angles. 
For  a  5  inch  leg  use  4  x  3  x  3-8  angles. 
For  a  4  inch  leg  use  3  x  3  x  3-8  angle. 

(87)  A  pair  of  stiffeners  shall  be  used  over  each 
end  of  each  end  bearing,  and  when  pin  bearings  are 
used,  there  shall  be  an  additional  pair  over  the  center  of 
each  bearing. 

(88)  Fillers,  equal  in  thickness  to  the  flange  angles, 
shall  be  used  under  all  stiffeners,  except  at  sp'ice  pomts 
where  the  splice  plates  serve  for  fillers. 

(89)  When  side  plates  are  used  under  the  flange 
angles,  the  fillers  shall  be  of  the  same  thickness  as  the 
side  plates,  and  the  stiffeners  may  be  crimped  over  the 
flange  angles. 

(90)  The  pitch  of  rivets  uniting  the  flange  angles 
to  the  web  plate  shall  not  exceed  that  given  by  the  for- 
mula : 

p  =  r  d  4-  s 
where  p  =  Pitch  of  rivets 

r  =  Value  of  one  rivet 

d  =  Distance  between  rivet  lines 

s  =  Shear  at  the  point  under  consideration. 


—  20- 

(91 )  The  pitch  of  rivets  between  stiffened  shall 
be  uniform,  and  shall  be  determined  from  the  shear  at 
the  siffener  nearer  the  end  of  the  girder,  but  in  no  case 
shall  the  pitch  of  rivets  in  each  gauge  line  exceed  9 
inches. 

Bradn*  (92)   Deck  girders  less  than  30  feet  in  length,  shal*. 

be  braced  in  the  plane  of  the  top  flanges,  and  shall 
have  cross  frames  at  ends  and  at  intermediate  pohits. 
Deck  girders  30  feet  or  more  in  kngth  shall  have  top 
and  bottom  bracing,  and  cross  frames  at  the  ends  and  at 
intermediate  points.  The  bracing  shall  generally  take 
the  form  of  a  Warren  truss,  the  diagonal  members  in 
the  top  system  being  made  of  two  angles  back  to  back, 
and  in  the  bottom  system,  of  a  single  angle.  Thn  di- 
agonals in  the  cross  frames  shall  consist  of  two  angles 
"m  each  direction,  the  top  and  bottom  horizontals  of  two 
angles  for  the  end  frames,  and  of  one  or  two  angles  for 
the  intermediate  frames  as  may  be  required.  All  angles 
shall  be  connected  at  their  ends  so  as  to  develope  their 
full  strength. 

(93)  Through  girders  shall  have  one  set  of  ad- 
justable, horizontal,  lateral  bracing,  generally  using  the 
floor  beams  for  struts.     The  floor  beams  shall  be  at^ 
tached  to  the  main  girders  through  gusset  plates  ex- 
tending the  full  depth  of  the  girders.     When  the  gus- 
set plate  extends  more  than  96  times  its  thickness  above 
or  below  the  beam,  there  shall  be  two  3x2  1-2  inch 

angles  riveted  to  its  edge. 
End  Finish 

(94)  All  through  girders  shall  have  their  upper 

corners  rounded  and  the  first  flange  plate  shall  extend 
down  to  the  bottom  of  the  girder. 

(95)  The  ends  of  all  deck  girders  shall  be  covered 


Ends  Faced 


Pin-connected 

Eridges 

Compression 

Members 


Batten* 


Lattice 


with  a  p'ate  riveted  to  the  end  stiiTener  angles,  and  in 
addition,  there  shall  be  corner  cover  plate  riveted  over 
each  upper  corner  of  the  girder. 

(96)  When  the  detail  will  permit,  the  ends  of  all 
stringers  and  floor  beams  shall  be  faced  and  extra  ma- 
terial must  be  provided  in  the  end  angles  to  allow  for 
planing. 

(97)  End  post  and  top  chord  sections  shall  gen- 
erally consist  of  two  rolled  or  built  channels,  joined  on 
their  upper  flanges  by  a  cover  plate,  and  on  their  lower 
flanges  by  batten  plates  near  the  ends  and  diagonal 
lattice  bars  between  the  battens. 

(98)  Intermediate   posts    shall    generally    consist 
of  two  rolled  or  built  channels  joined  on  both  flanges 
by  battens  near  the  ends,  and  diagonal  lattice  bars  be- 
tween the  battens. 

(99)  The  length  of  the  batten  plate  shall  not 
be  less  than  the  greatest  width  of  the  member  and 
its  thickness  shall  not  be  less  than  1-40  of  its  un- 
supported width.     No  batten  shall  have  less  than 
three  rivets  along  each  edge. 

(100)  Lattice  bars  shall  have  a  width  of  at 
least  three  diameters  of  the  rivet  and  a  thickness 
of  at  least  1-50  of  the  unsupported  length.     The 
spacing  of  the  bars  shall  be  such  that  the  angle  be- 
tween the  bar  and  the  center  line  of  the  section 
shall  not  be  less  than  60  degrees,  for  single  lattice 
and  45  degrees  for  double  lattice  and  the  distance 
between  rivets  in  either  channel  flange  shall   not 
exceed   60    times    the   thickness    of    the    flange. 
Double  lattice  bars  shall  have  a  rivet  at  each  inter- 
section.    On  large  or  wide  sections,  3x2  inch  an- 
gles shall  be  used  instead  of  bars  for  lattice. 


OF 


THE 

UNIVERSITY 

OF 


Riveting 


Pin-plates 


Pin-holes 


Splices 


Eyebars 


— 22 — 

(101)  At  each  end  of  any  compression  mem- 
ber  for   a   distance   equal   to  twice   its   width   the 
pitch  of  the  rivets  shall  not  exceed  four  diameters 
of  the  rivet  and  throughout  the  remaining-  portion 
of  the  member  the  pitch  shall  net  exceed  6  inches 
or  16  times  the  thickness  of  the  thinnest  plate  or 
angle. 

(102)  Where  necessary-  pin  holes  shall  be  re- 
inforced by  pin  plates.    At  points  where  the  stress 
is  transmitted  entirely  to  the  pin,  the  first  pin  plate 
shall  extend  back  from  the  pin  far  enough  to  over- 
lap the  batten  plate  by  at  least  6  inches. 

(103)  When  computing  the  necessary  num- 
ber of  rivets   for  the  pin   plate,  the  bearing  per 
square  inch  between  the  pin   and  pin  plate  shall 
be  assumed  the  same  as  between  the  pin  and  main 
member. 

(104)  Pin   holes   shall   be  placed   with   ref- 
erence to  the  center  of  moments  of  the  section  and 
they  shall  be  placed  enough  below  that  center  to 
balance  the  bending  moment  due  to  the  weight  of 
the  member. 

(105)  Splices  in  the  top  chord  shall  gener- 
ally be  made  a  short  distance  from  the  pin  point 
and  all  splices  shall  be  equiped  with  splice  plates 
and  cover  plates  to  hold  the  members  truly  in  po- 
sition. 

(106)  The  main  diagonal  and  bottom  chord 
members  shall  be  made  of  die  forged  eyebars,  con- 
structed in  such  a  way  that  when  tested  to  destruction 
they  will  break  in  the  main  body  of  the  bar  rather  than 
in  the  head. 


Stiffened 


Sections 


Aljustab'e 

Members 


Stringers 


Beams 


Bracing 


Top  Slruts 


Knees 


Cross  Bracing 


Porlals 


(107)  The  first  two  panels  of  bottom  chord  at 
each  end  of  ihe  span  arid  the  hip  verticals  or  long  sus- 
penders  shall   be   stiffened.      These   members   may  be 
laced  eyebars. 

(108)  All  counters  and  lateral  rods  shall  be  ad- 
justable by  means    of    open    turnbuck'es  or    device*. 
The  threaded  ends  of  all  rods  must  be  upset.     The 
ends  of  all  rods  attached  to  pins  shall  have  loop  eyes 
with  the  distance  from  the  back  of  the  pin  to  the  apex 
of  the  loop  not  less  than  three  diameters  of  the  pin. 

Only  iron  bars  may  have  loop  eyes. 

(109)  The  stringers  shall  preferably  be  framed 
in  between  the  floor  beams ;  if  placed  on  top  they  sha'.l 
have  a  cross  frame  at  each  end. 

(no)  The  floor  beams  shall  be  built  in  between 
the  posts  of  the  main  trusses  and  shall  be  connected 
to  the  same  through  gussets  extending  at  least  3  feet 
above  the  top  of  the  beam. 

(in)  All  pin  connected  bridges  shall  have  ad- 
justable bracing  in  the  planes  of  the  top  and  bottom 
chords  and  as  near  as  practicable  to  the  pin  center  lines. 
(112) The  top  struts  shall  generally  be  made 

of  four  angles  laced  the  full  depth  of  the  ch:rd. 

(113)  When  the  distance  from  rail  to  top 
strut  does  not  exceed  25  feet,  knee  braces  shall  be 
used  connecting  the  top  struts  to  the  vertical  posts 
of  the  main  trusses. 

(114)  When  the  distance  from  rail  to  top  strut 
exceeds  25  feet,  sub-struts  and  cross-bracing  shall 
be  used  instead  of  knee  braces. 

(115)  The  end  posts  shall  be  connected  by 
portal  struts,  so  designed  as  to  effectively  transmit 


Viaducts  or 
'_    Trestles 

Type 
Bents 
Towers 
Rocker 

Batter 
Bearings 

Anchorage 


Bracing 


-24— 

the  wind  stresses  from  the  top  lateral  system  to 
the  bridge  seat.  Portals  shall  be  as  deep  as  the 
specified  clearance  will  permit  and  brackets  usual- 
ly curved,  shall  be  used  connecting  the  bottom 
flange  of  the  portal  strut  to  the  end  posts. 

(116)  Viaducts   shall   generally  consist  of  plate 
or  open  web  riveted  girders,  supported  by  bents  and 
towers. 

(117)  -A  bent  consists  of  a  pair  of  columns  braced 
transversely. 

(118)  A   tower   consists   of   two    bents    braced 
longitudinally. 

(119)  When  a  bent  is  used  separately  it  shall  be 
designed  as  a  rocker  and  shall  have  pin  ends  at  top  and 
"bottom. 

(120)  Each  column  in  a  bent  shall  have  a  batter 
of  not  less  than  one  horizontally  to  six  vertically. 

(121)  Provision  shall  be  made  at  the  foot  of  each 
bent  for  expansion  and  contraction  due  to  changes  in 
temperature  of   150   degrees   Fahrenheit.     All   sliding 
surfaces  shall  be  planed  and  anchor  bolt  holes  slotted 

(122)  All  bents  and  towers  shall  be  anchored  to 
the  foundations  in  such  a  way  as  to  be  safe  against 
overturning  whether  loaded,  unloaded  or  loaded  with 
empty  cars. 

(123)  When  a  viaduct  is  located  on  a  curve,  the 
effects  of  centrifugal  force  must  be  considered  in  addi- 
tion to  the  wind  loads. 

(124)  Transversely   all    bents    shall   be    braced 
with  angles  against  all  effects  of  wind  and  centrifugal 
force.     Longitudinally  all  towers  shall  be  braced  with 


Swing  Bridges 
Floor  System 

Trusses 


Turntable 


Disc  Center 


Roller  Center 


—25— 

angles  or  channels  against  the  effects  of  stopping  a  train 
on  the  viaduct.  Transverse  struts  shall  be  used  at  the 
bottom  of  a'l  bents  and  longitudinal  struts  at  the  bot- 
tom of  all  towers  strong  enough  to  slide  the  cohimns 
when  changes  in  temperature  occur. 

(125)  The  floor  system  of  swing  bridges  shall 
be  designed  the  same  as  for  fixed  spans. 

(126)  W<<th  the  bridge  closed,  the  trusses  shall 
be  designed  under  the  same  unit  stresses  as  for  fixed 
spans,   but   with   the  bridge  open  the  dead  load  unit 
stresses  shaM  not  exceed  three-quarters  of  the  dead  load 
unit  stresses  for  fixed  spans. 

(127)  The  turntable  may  be  center  bearing,  rim 
bearing  or  a  combination  of  the  two.     If  the  combina- 
tion table  is  used  the  supporting  girders  shall  be  so  ar- 
ranged that  some  definite  and  known  portion  of  the 
load  will  be  carried  to  the  center. 

(128)  When  a  disc  center  is  used  there  shall 
be  three  discs,  the  upper  and  lower  of  hard  steel 
and  the  center  of  phosphor  bronze,  and  so  arrang- 
ed that  all  sliding  will  occur  between  the  steel  and 
phosphor  bronze  discs.     The  discs  shall  have  oil 
grooves  and  the  center  shall  be  so  arranged  that 
the  discs  may  be  kept  flooded  with  oil. 

(129)  When  a  roller  center  is  used  the  roll- 
ers shall  be  turned  truly  conical  and  shall  be  pro- 
vided with  a  band  to  ho1d  them  in  position.     Al! 
rollers  shall  be  of  hard  steel  and  will  travel  be- 
tween tracks  of  hard  steel,  planed  to  a  true  bevel  to 
fit  the  rollers.     The  center  shall  rle  so  arranged 
that  the  rollers  may  be  kept  flooded  with  oil. 


£im  Bearing  (!3o)     When  a  rim  bearing  table  is  used,  the 

load  shall  be  conveyed  by  means  of  a  circular  drum 
to  a  set  of  cast  steel  wheels  turned  truly  conical 
which  travel  between  two  steel  tracks,  one  above 
attached  to  the  drum  and  one  below  attached  to  the 
foundation.  The  tracks  shall  be  planed  circular 
and  to  a  true  bevel  to  fit  the  wheels. 

(131)  The  bottom  track,  wheels  and  drum 
shall  be  connected  to  an  iron  casting-  at  the  center 
of  the  table  in  order  to  keep  all  properly  centered. 
The  drum  shall  be  connected  by  means  of  radial 
struts  to  a  hub  which  is  free  to  rotate  about  the 
center  casting.     The  wheels  shall  be  connected  by 
means  of  spider  rods  to  another  similar  hub. 

(132)  There  shall  be  two  circular  bands  to 
keep  the  wheels  properly  spaced    one  inside  and 
the   other   outside  the   wheels.     The   outer  band 
shall  be  made  in  short  sections  so  arranged  that 
any  wheel   may  be  easily   removed   and   replaced 
without  disturbing  the  others.     Each   spider  rod 
shall  extend  through  a  wheel  arid  both  bands  and 
shall  be  provided  with  nuts  and  washers  making 
it  possible  to  adjust  the  conical'  wheels  to  a  shorter 
or  longer  radius. 

Latches  (I33)  Both  ends  of  the  bridge  shall  be  provided 

with  strong  latches  arranged  to  close  automatically  and 
to  be  opened  from  the  tender's  house. 

End  Lifts  (*34)  End  lifts  shall  be  provided  for  raising 

both  ends  of  the  bridge  by  an  amount  sufficient  to  pre- 
vent the  lifting  of  either  end  clear  from  its  seat  under 
any  position  of  the  load.  They  shall  be  so  arranged 
that  they  may  be  operated  from  the  tender's  house, 


Raft  Lifts 


End  Signals 


I»Iaohinery 


Cables 


Motors 


Material 


Tender's  House 


—27— 

(135)  Both  ends  of  the  bridge  shall  be  equipped 
with  suitable  rail  lifts  arranged  to  be  operated  from 
the  tender's  house. 

(136)  At  each  shore  end  of  the  bridge  there  shall 
be   an   automatic   signal   so  arranged  that  the  bridge 
cannot   be   opened   without   setting   the   signal   to  the 
position  of  danger. 

(T37)  Under  this  head  shall  be  included  all  mo- 
tors, cables,  wires,  switches,  controllers,  lightening  ar- 
resters, electric  heaters,  gears,  shafting,  rack  and  such 
other  equipment  as  is  necessary  to  make  a  complete  and 
perfect  plant  for  the  operation  of  the  bridge  by  both 
hand  and  electric  power. 

(138)  The  necessary  sub-marine  cables  shall 
be  furnished  by  the  Contractor  for  the  superstruc- 
ture, but  shall  be  put  in  place  by  the  Contractor  for 
the  substructure. 

(139)  The   motor   for    turning  the    bridge 
shall  be  of  sufficient  capacity  to    turn    the    bridge 
through  a  quadrant  in  one  minute,  starting  from 
rest  and  ending  at  rest. 

( 140)  The  motors  for  operating  the  end  lifts, 
rail  lifts  and  end  signals  may  be  placed  at  the  ends 
of  the  bridge. 

(141)  All   shafting  shall  be  medium   steel, 
all  pinions,  gears,  rack  and  shaft  bearings  shall, 
be  cast  iron  or  cast  steel.    All  shaft  bearings  shall 
be  babbitted. 

(142)  A  tender's  house  of  neat  design  shall  be 
provided  at  the  center  of  the  bridge,  preferably  over  the 
track,  in  which  all  controllers,  switches,  lightening 
arresters,  heaters  and  other  electric  equipment  shall  be 


SHOP  WORK 
first  Class 

Straightening 


Punching 


Reaming 


Drilling 


Riveting 


pladed.     When  necessary  a  stairway  shall  he  provided 
for  the  tender's  house. 

(143)  All  shop  W6rk  shall  he  first  class  in  every  par- 
ticular. 

(144)  Wheri  necessary  all  material  shall  he  straight- 
ened before  being  laid  oft".     After  punching  and  before  as- 
sembling all   material   shall  be  carefully   straightened   and 
freed  from  all  twists  and  buckles.     AM  web  plates  must  be 
free  from  buckles. 

(145)  All   straightening  shall  be  done  in  presses  of 
between  rolls.    Hammering  will  not  be  allowed. 

(146)  All  punched  holes  shall  be  fnpcte  with  a  punch 
one-eighth  of  an  mch  smaller  in  diameter  than  the  rivet. 
The  die  shall  not  be  more  than  one-sixteenth  of  an  inch 
greater  in  diameter  than  the  punch. 

(147)  After   punching   and    assembling   r\\l   punched 
holes  shall  be  reamed  to  a  diameter  not  more  than  one-six- 
teenth of  an  inch  greater  than  the  diameter  of  the  cold  rivet. 
After  reaming  all  holes  shall  be  smooth,  showing  that  metal 
has  everywhere  been  removed  around  the  hole. 

(147)  When  any  metal  is  too  th;ck  for  successful 
punching,  all  hol'es  shall  be  drilled.  All  rivet  holes  in  eyej 
bars  shall  be  drilled  and  all  pin  holes  shall  be  drilled  or 
bored. 

(149)  All  shop  rivets  so  far  as  possible  shall  be  driven 
with  a  machine  capable  of  holding  the  pressure  after  the 
rivet  is  driven.  AM  rivets  shall  be  driven  tight  and  upset 
so  as  to  completely  fill  the  hole.  No  calking  or  cupping  will 
be  allowed.  Rivets  of  the  same  size  shall  have  the  snnie  si7<fj 
heads  and  the  heads  must  be  concentric  with  the  rivet.  All 
toose  or  poor  rivets  must  be  cut  out  and  replaced. 


—29— 

Facing  (T5°)     The   ends   of   all   beams   and   stringers,   when 

built  in.  shall  be  faced  square  and  true  to  length. 

(151)  Abutting  ends  of  all  compression  members 
shall  be  faced  in  a  machine  so  that  their  ends  will  be  in  per- 
fect contact  when  in  p'ace  in  the  bridge. 

Fitting  (I52)     The  ends  of  all  stiffenerj  shall  be  trimmed  to 

fit  tight  against  the  flange  angles  and  all  fillers  under  the 
stiffeners  shall  be  made  to  fit  tight  against  the  edges  of  the 
flange  angles. 

Planing  (T53)     All  abutting  ends  of  web  plates  for  plate  gird- 

ers shall  be  planed. 

( 154)  The  edges  of  all  sheared  plates  shall  be  planed. 

(155)  All  shoe  and  masonry  plates  shall  be  planed  30 
that  the  two  faces  of  each  plate  are  truly  parallel. 

Pin  Holes  (TS6)      Pin  holes  in   riveted  members   shall  be  bored 

truly  parallel  to  each  other  and  at  right  angles  to  the  axis 
of  the  member. 

(157)  Pin  holes  in  eyebars  must  be  in  the  axis  of  the 
bar,  in  the  center  of  the  heads  and  at  right  angles  to  the 
planes  of  the  flat  surfaces.     When  all  the  bars  of  the  same 
member  are  piled  together,  the  pins  shall  pass  through  both 
ends  of  ali  bars  without  driving. 

(158)  The  diameter  of  the  pin  hole  shall  not  exceed 
that  of  the  pin  by  more  than   1-50  of  an  inch  except  for 

.  pins  over  4  inches  in  diameter  when  this  excess  shall  not 
exceed  1-32  of  an  inch. 

(159)  All  pins  and  rollers  shall  be  turned  smooth  and 
true  to  size. 

(160)      All  eyebars  shall  be  made  from  bars  of  full 
Material  section  and  free  from  folds,  cracks,  or  other  defects. 

Heads  (161)     The  heads  shall  be  made  by  upsetting  and 

forging  the  bars.     No  head  shall  be  more  than  one-six- 


Annealing 


Adjustable  Rods 
Loop  Eyes 


Upsettirg 


Annealing1 

Painting 
Cleaning 


Before 

Assembling' 

inaccessible 

Farts 


Machined 

Surfac«s 


—30— 

teetith  of  an  inch  thicker  than  the  body  of  the  bar.  All 
heads  shall  be  so  proportioned  and  made  that  the  bars 
will  break  in  the  body  of  the  original  bar  arid  riot  in  the 
head  or  neck. 

(162)  After  the   heads   are  Completed  the  bars 
shall  be  annealed  by  being  heated  to  a  bright  red  heat 
throughout  their  entire  length  and  then  allowed  to  cool 
slowly. 

(163)  The  ends  of  all  rods  attached  to  piiis  shall 
have  loop  eyes  formed  by  bending  the  bar  around  a  pri 
arid  weMing  the  end  to  the  main  body  of  the  bar.     All 
loop  eyes  shall  have  holes  bored  to  fit  the  pin.     Only 
iron  bars  may  have  loop  eyes. 

(164)  The  ends  of  all  rods  that  take  nuts,  turn- 
buckles  or  devices  shall  have  their  ends  enlarged  by 
upsetting  the  bar.     The  cross-sectional   area   of  the1 
upset  end  at  the  root  of  the  thread  shall  be  at  least  16 
per  cent,  greater  than  the  original  area  of  the  bar  and 
under  test  to  destruction  the  bar  must  break  in  the 
main  body  and  not  in  the  upset  end. 

(165)  Steel  bars  with   upset  ends   shall  be  ari- 
nealed  the  Same  as  eyebars.     See  paragraph  162. 

(166)  AH   material   shall  be  thoroughly  cleaned 
from  dirt  rust  and  scale  before  any  oil  or  paint  is  ap- 
plied.    Wire  brushes  and  steel  scrapers  shall  be  used 
when  necessary. 

(167)  All  surfaces  doming  in  Contact  shall  have' 
One  coat  of  red  lead  paint  before  assembling. 

(168)  All  parts  not  accessible  after  erection  shait 
have  two  coats  of  red  lead  paint. 

(169)  All   machine  finished   surfaces   shall   have* 
a  coat  of  white  lead  and  tallow  before  shipment. 


Other  Parts 


Application 


FIELD  WORK 
Ready  for  Rails 

Floor  Deck 


Falsework 


Interrupting 

Traffic 


(170)  All  other  parts  shall  have  one  coat  of  boil- 
ed linseed  oil  before  shipment. 

(171)  No  oil  or  paint  shall  be  applied  in  wet 
or  freezing  weather,  or  when  the  metal  is  not  dry,  and 
no  coat  shall  be  applied  until  the  one  before  is  thor- 
oughly dried.     No  material  shall  be  painted  until  after 
it  has  been  examined  and  accepted  by  the  inspector. 

(172)  All   oil    and   paint   shall   be   applied   with 
good   thick  brushes    (round   preferred)     with    elastic 
bristles,   by   skilled   painters   and   shall  be  thoroughly 
brushed  out  and  worked  into  all  open  spaces  and  so 
applied  as  to  completely  cover  the  surface. 

(173)  AH  oil,  when  applied,  shall  be  heated  to  a 
temperature  of  from  150  to  200  degrees  Fahrenheit. 

(174)  All  red  lead  paint  shall  be  kept  well  stirred 
while  it  is  being  used. 

(175)  Unless  otherwise  specified  all  bridges  shall  be 
erected  by  the  Contractor  ready  for  the  rails. 

(176)  All  rails,  splices  and  fastenings  for  the  same 
shall  be  furnished  and  put  in  place  by  the  Railway  Company ; 
all  ties  and  guard-rails  shall  be  furnished,  delivered  at  the 
bridge  site,  by  the  Railway  Company,  but  will  be  put  in  place 
by  the  Contractor,  all  floor  deck  bo'ts,  washers,  nut  locks, 
etc.,  being  furnished  by  the  Contractor.     See  paragraphs  18 
to  21  inclusive. 

(177)  All  falsework  timber,  bolts,  etc.,  shall  be  fur- 
nished and  put  in  place  by  the  Contractor  and  shall  be  re- 
moved by  him  after  completion  of  the  work. 

(178)  When  a  bridge  is  being  erected  on  a  line  al- 
ready in  operation,  the  work  shall  be  done  without  inter- 
rupting traffic,  except  as  arrangements  are  made  for  such 
interruption. 


Renewal 


Anchorage 


Watchmen 


Laws 


Risks 


Reaming 


Riveting 


turned  Bolts 

hlot  Nuts 

Painting 
Cleaning 

Rivet  Heads 


(179)  In  case  of  a  renewal  the  Contractor  shall  take1 
down  the  old  bridge  and  pile  the  same  on  the  bank  or  load 
it  on  cars  as  may  be  directed. 

(180)  The  Contractor  shall  drill  all  the  necessary  an- 
chor bolt  holes  in>  the  masonry,  and  shalfl  set  the  bolts  in 
place,  fastening  the  same  with  neat  Portlarid  cenvnit  mortar. 

(181)  When  necessary  the  Contractor  shall  provide 
watchmen  and  other  safeguards  during  erection. 

(182)  The  Contractor  shall  comply  with  a'l  laws  rind 
ordinances  whenever  there  are  ariy  applicable  to  the  work  iri 
execution. 

(183)  The  Contractor  shall  assume  all  risks  of  acci- 
dents or  from  floods  or  other  causes  until  the  final  comple- 
tion of  the  work. 

•(184)'  When  assembling  the  work  in  the  field,  any 
inaccuracies  in  the  rivet  holes  must  be  corrected  by  reaming, 
drifting  will  not  be  allowed.  t)riit  pins  may  only  be  used  td 
bring  the  pieces  together. 

(185)  All  rivets  must  have  lull  heads,  concentric  with 
the  rivet,  of  a  uniform  size  for  the  same  size  of  rivet  and 
m'ust  be  driven  so  as  to  completely  fill  the  holies.    Loose  of 
poor  rivets  must  be  cut  out  ind  replaced. 

(186)  Where  it  is  impossible  to  drive  rivets  in  the1 
field,  turned  bolts  may  be  used  provided  they  are  tlirned  to  a 
driving  fit. 

(187)  Pilot  nuts  shall  be  used  on  pins  to  protect  the1 
threads  when  the  pins  are  being  driven. 

(188)  Before  applying  the  field  coats  of  paint,  all 
members  shall  be  cleaned  from  all  blisters,  loose  paint 
and  dirt. 

(189)  After    erection    and    before   applying    the 


Flfst  Coat 


Second  Coat 


Application 


QUALITY 

OF  MATERIAL 

Wrought  steel 
Process 

Finish 


Variation 


—33— 

finishing  Coats  all  heads  of  field  rivets  shall  he  painted 
with  the  same  material  as  used  for  the  first  field  coat. 

(190)  After  erection  all  accessible  parts  shall  re- 
ceive one  coat  of  "Red  Lead  Metal  Preservative/* 

(191)  After  the  "Red  Lead  Metal  Preservative'' 
is  thoroughly  dry  all  accessible  parts  shall  receive  a 
second  field  coat  which  shall  be  a  high  grade  graphite 
or  carbon  paint. 

(192)  No  paint  shall  be  applied  in  wet  or  freez- 
ing weather,  or  when  the  metal  is  not  dry.     All  paint 
shall  be  app/ied  with  good  thick  brushes   (round  pre- 
ferred) having  elastic  bristles  and  by  skilled  painters. 
All  paint  must  be  well  rubbed  onto  the  surface  and 
Xvorked  into  all  open  spaces  and  so  applied  as  to  com- 
pletely cover  the  surface. 

(193)  All   wrought  steel  shall  be  made  by  the 
Open  hearth  process. 

(194)  The  finished  product  shall  be  true  to  size 
and  shape  and  free  from  imperfections  such  as  cracks 
or   roughness.     When   two   or    more    universal     mill 
plates  of  the  same  width  come  together  in  the  finished 
Work  they  must  be  of  uniform  width  and  their  edges 
must  not  be  beveled. 

(195)  No  greater  variation  than  2\  per  cent,  shall 
be  allowed  between  the  estimated  and  actual  weight  of 
any  piece  of  material  except  for  wide  plates  where  the 
actual  weight  may  exceed  the  estimated  weights  by  the 
amounts  given  in  the  following  table : 


—34— 


Width  of  Plate  in  Inches. 


Phosphorus 


Test  Pieces 


Ultimate 

Strength 


Thickness 

in   Inches.  |     48  to  75       |     75  to  100. 


O/er  JOG. 


1-4 

10  per  cent.   14  per  cent. 

18  per  cent. 

5-16- 

8  percent.  |  12  percent. 

16  per  cent. 

3-8 

7  per  cent. 

10  per  cent. 

13  percent. 

7-16 

6  per  cent. 

9  per  cent. 

10  per  cent. 

1-2 

5  per  cent. 

7  per  cent. 

9  per  cent. 

9-l6 

4^  per  cent. 

6J  per  cent. 

8J  per  cent. 

5-8 

4  per  cent. 

6  per  cent. 

8  per  cent. 

Over  5-8 

3-J  per  cent.  |  5  per  cent. 

6J  per  cent. 

(196)  The  amount  of  phosphorus  shair  not  ex- 
ceed .08  per  cent,  in  stee.  made  in  an  acid  furnace  and 
.04  per  cent,  in  steel  made  in  a  basic  furnace. 

(197)  The  properties  of  stee!  shall  be  determin- 
ed from  test  prices  cut  from  the  finished  product,  rep- 
resenting each  melt. 

(198)  The  test  pieces,  about  12  inches  long,  shall 
be  planed  or  turned  to  a  uniform  area  of  not  less  than 
J  of  a  square  inch  for  a  length  of  10  inches. 

(199)  Pieces  representing  annealed  bars  may  be 
annealed  before  testing. 

(200)  When  a  me!t  is  rolled  into  several  varie- 
ties of  material  a  test  piece  shall  be  taken  from  each  va- 
riety. 

(201)  The     ultimate     strength    of    the    several 
grades   of   steel,   as   determined   from   the  test  pieces, 
shall  be  within  the  following  limits : 

Hard  steel,  70,000  to  78,000  Ibs.  per  square  inch. 
Medium  steel  62,000  to  70,000  Ibs  per  square  inch. 
Soft  steel,  54,000  to  62,000  Ibs.  per  square  inch. 
Rivet  steel,  50,000  to  58,000  Ibs.  per  square  inch. 


Elastic  Limit 
Elongation 


Reduction 

of  area 


Fracture 
Bending 

Hard  Steel 


Medium  Steel 


Soft  and  Rivet 
Steel 


Drifting 


—35— 

(202)  The  elastic  limit  shall  not  be  less  than  55 
per  cent,  of  the  ultimate  strength. 

(203)  The  elongation  in  8  inches  shall  not  be  less 
than— 

1 8  per  cent,  for  hard  steel. 
22  per  cent,  for  medium  steel. 
24  per  cent,  for  soft  steel. 
26  per  cent,  for  rivet  steel. 

(204)  The  reduction  of  area  at  the  point  of  frac- 
ture shall  not  be  less  than — 

35  per  cent,  for  hard  steel. 
40  per  cent,  for  medium  steel. 
45  per  cent,  for  soft  steel. 
48  per  cent,  for  rivet  steel. 

(205)  The  entire  fracture  must  be  silky. 

(206)  A  piece  of  each  test  piece  shall  be  bent 
cold  1 80  degrees. 

(207)  No   specimen    from   hard   steel    shall 
show  any  signs  of  cracks  until  the  diameter  of  the 
circle  around  which  the  bar  is  bent  becomes  less 
than  3  times  the  thickness  of  the  specimen. 

(208)  No  specimen  from  medium  steel  shall 
show  any  signs  of  cracks  until  the  diameter  of  the 
circle  around  which  the  bar  is  bent  becomes  less 
than  the  thickness  of  the  specimen. 

(209)  Each  specimen  from  soft  or  rivet  steel 
shall  bend  180  degrees  and  close  upon  itself  with- 
out sign  of  crack  or  flow  on  the  convex  surface. 

(210)  The  ductility  of  medium  and  soft  steel 
shall  be  such  that  a  punched  hole,  the  center  of  which 
is  not  more  than  i£  inches  from  the  sheared  or  rolled 
edge  of  any  piece  may  be  enlarged  by  drifting  to  a  diam- 


Duplicate  Tests 

Marking1 
Eydtar  Tests 


-36- 

eter  50  per  cent,  greater  than  the  original  hole  without 
cracking  the  specimen  at  any  point. 

(211)  Duplicate   tests   may   be   made   when   the 
sample  fulfills  all  but  one  of  the  requirements.     If  the 
second  test  and  the  average  of  the  two  tests  meet  all 
the  requirements,  the  melt  may  be  accepted. 

(212)  All  material  shall  be  plainly  stamped  with 
a  number  identifying  the  melt. 

(213)  The  eyebars  required  for  tests  and  those 
for  the  structure  shall  be  made  at  one  time.     The  test 
bars  to  be  selected  by  the  Inspector,  must  be  fair  aver- 
age specimens  of  those  which  would  be  classed  as  good 
bars  acceptable  for  the  work.     No  bar  which,  is  known 
to  be  defective  shall  be  selected  for  testing. 

(214)  These  bars  will  be  required  to  develope  a 
minimum  stretch  of  14  per  cent,  before  breaking  if  of 
soft  steel  and   12  per  cent,  if  of  medium  steel.     The 
elongation  to  be  measured  on  a  gauged  length  of  10 
feet  including  the  fracture. 

(215)  If  medium  steel  is  used  the  bars  shall  show 
an   ultimate   strength   of   not   less   than   62,000 — 9.000 
(area  — :--  perimeter)   and  if  soft  steel  not  less  than 
54,000 — 8,000    (area   — :—   perimeter).        The     elastic 
limit  in  all  cases  shall  not  be  less  than  55  per  cent,  of 
the  ultimate  strength. 

(216)  In  general  bars  will  be  required  to  break 
in  the  body.     When  a  bar  breaks  in  the  head  but  de- 
velopes  14  per  cent,  elongation  before  breaking,  a  second 
bar  shall  be  selected  from  the  same  lot.     If  this  bar 
breaks  in  the  body  and  the  average  elongation  of  the 
two  bars  is  not  less  than  16  per  cent.,  the  bars  of  this  lot 
may  be  accepted. 


Wrought  Iron 
Grade 


Test  Pieces 


Ultimate 

Strength 


Elastic  Limit 

Elongation 

Bending 


—37- 

(217)  If  more  than  one-third  of  all  the  bars  tested 
break  in  the  head,  this  shall  be  deemed  sufficient  cause 
for  the  rejection  of  the  entire  bill  of  eybars. 

(218)  Tests  of  full  sized  sections  that  meet  the 
requirements  shall  be  paid  for  at  cost  less  the  scrap  value 
of  the  material.     Tests  that  fail'  to  meet  the  require- 
ments will  be  at  the  expense  of  the  Contractor. 

(219)  All  wrought  iron  shall  be    be    the    best 
doable  rolled  and  double  refined  iron     It  must  be  tbugh 
fibrous,  uniform  in  quality,  thoroughly  welded  in  roll- 
ing and  finished  straight  and  smooth.     It  must  be  free 
from  flaws   blisters,  cinder  spots,  cracks  and  imperfect 
edges.     It  must  be  worked  from  the  muck  bar  and  no 
steel  scrap  will  be  allowed  in  its  manufacture. 

(220)  Test  pieces  shall  be  prepared  the  same  as 
for  wrought  steel.    See  paragraphs  197  to  200  inclusive. 

(221)  The  ultimate  strength  as  determined  from 
the  test  pieces   shall/  no*   be  less   than   50,000  pounds 
per  square  inch. 

(222)  Tension  tests  of  full  sized  bars  must  show 
an  ultimate  strength  of  at  least  52,000 — 7,000   (area 
--:—  perimeter)  in  pounds  per  square  inch. 

(223)  The  elastic  limit  in  no  case  shall  be  less 
than  26,000  pounds  per  square  inch. 

(224)  The  elongation  in  8  inches  shall'  be  at  least 
1 8  per  cent. 

(225)  All  iron  must  bend  co!d  180  degrees  to  a 
curve,  the  diameter  of  which  is  not  more  than  twice 
the  thickness   of  the  piece  without   cracking.      When 
nicked  and  bent  the  piece  must  show  no  signs  of  being 
brittle,  but  shall  bend  and  break  gradually,  showing  a 
uniform  fibrous  fracture. 


Cast  Steel 
Process 

Phosphorus 
Coupon 

Annealing" 
Blow  holes 


Ultimate 
Strength 


Elastic  limit 


Elongation 


Reduction 
of  area 


Cast  iron 
Grade 


-38- 

(226)  Rivet  iron  must  be  capable  of  being  bent 
double  and  c1osed  upon  itself,  hot  or  cold,  without  sign 
of    fracture    on    the    convex    surface.        When    nicked 
and  broken  the  fracture  must  be  fibrous. 

(227)  All  steel  castings  shall  be  made  by  the  open 
hearth  process  and  shall  be  trre  to  pattern  and  of  work- 
manlike finish. 

(228)  The  amount  of  phosphorus  shah  not  ex- 
ceed .08  per  cent. 

(229)  All  castings  shall  be  made  with  a  coupon 
for  testing  which  shalli  not  be  cut  off  until  after  the 
castings  have  been  annealed. 

(230)  All  casting's  shall  be  thoroughly  annealed. 

(231)  When  the  bearing  surface  of  any  casting 
is  finished,  there  sha'l  be  no  blow  hole  visible  exceeding 
one  inch  in  length  or  exceeding  one-half  square  inch  in 
area.    The  length  of  blow  holes  cut  by  any  straight  line 
shall  never  exceed  one  inch  in  any  one  foot. 

(232)  The  ultimate  strength  as  determined  from 
a  f  of  an  inch  round  turned  from  the  coupon  shall  be 
from  65000  to  70000  pounds  per  square  inch. 

(233)  The  e^stic  limit  shall    not    be    less    than 
40000  pounds  per  square  inch. 

(234)  The  elongation  shall  not  be  less  than   15 
per  cent,  in  2  inches. 

(235)  The  reduction  of  area  at  the  point  of  frac- 
ture shall  not  be  less  than  20  per  cent. 

(236)  All  iron  castingss  shall  be  made  of  tough, 
gray  iron  and  shall  be  smooth,  sound,  true  to  pattern, 
of  workmanlike   finish   and   must   be    free   from   b1ow 
holes. 


—39— 

Coupon  (237)  One  casting  from  each  melt  shall  be  made 

with  a  coupon  about  one  inch  square  and  15  inches 
long,  for  testing. 

Tests  (238)  Tests  shall  be  made  on  the  coupons  by  ap- 

plying a  load  midway  between  supports  12  inches  apart. 
The  test  bars  shall  show  a  deflection  of  at  least  .15 
inches  and  develope  a  fiber  stress  of  at  least  43000 
pounds  per  square  inch. 

(239)  Castings  of  phosphor  bronze  shall  contain 
88  per  cent,  copper  and  12  per  cent,  phosphorized  tin. 
The  phosphorized  tin  shall  contain   5   per  cent,  phos- 
phorus. 

(240)  Each  casting  shall  be  made  with  a  coupon 
from  which  a  one  inch  cube  can  be  cut  for  testing. 

(241)  A  compression  test  on  this  cube  shall  show 
an  elastic  limit  of  not  less  than  20000  pounds.    The  per- 
manent set  on  the  test  cube  under  a  load  of   100000 
pounds  shall  not  exceed  one-s;xteenth  of  an  inch. 

(242)  A11    babbitt    metal    shall    be    composed    of    50 
parts  tin,  I  part  copper  and  5  parts  antimony. 

(243)  Al!  timber  sha'l  generally  be  white  oak  or  lon<^ 
leaf  yellow  pine.    It  shall  be  first-class  in  all  respects,  sawed 
true  and  of  full  size  and  must  be  free  from  sap  wood  and 
large  or  loose  knots. 

(244)  All  oil  shall  be  bored ;  linseed  oil  and  shall 
be  of  a  pa1e  yePow  color,  brilliant,  limpid,  drying  well, 
with  a  rich  luster,  and  having  a  pleasant  nutty  taste. 
Oil  of  a  greenish  or  dark  color,  cloudy  or  with  an  uncer- 
tain taste  will  not  be  accepted. 

Lead  (245)      All    red   lead   paint   shall   be   high   grade. 

When  properly  mixed  for  use  and  applied  to  a  smooth, 
vertical  surface,  it  should  neither  run,  separate  nor  sag. 


Phosphor  bronze 
Composition. 


Coupon 


Tests 


Babbitt  Metal 


Timber 


Paint 
Oil 


—4o— 

1st  Field  coat  (246)  The  first  field  coat  of  paint  shall  be  the 

"A"  brand  of  "Red  Lead  Metal  Preservative/'  made 
by  the  Lowe  Brothers  Co.,  of  Dayton,  Ohio. 

2nd  Field  coat  (247)  The  second  field  coat  of  paint  shall  be  one 

of  the  following:  First,  Graphite  paint  made  by  the 
Joseph  Dixon  Crucible  Co.,  of  Jersey  City,  N.  J. 
Second,  "Black  Metal  Coating  No.  1407,"  made  by  the 
Lowe  Brothers  Co.,  of  Dayton,  Oh;o. 

INSPECTION 

(248)     The  Railway  Companv  wi'l  emplov  an  Inspector 
Inspectors 

who  will  examine  and  test  all  material  before  any  work  is 
done  upon  it.  He  shall  have  free  access  to  the  mills  and 
shops  at  all  times  during-  the  construct'on  of  the  work  and 
shall  have  power  to  reject  material  when  the  material  or 
workmanship  does  not  comply  with  the  requirements  of 
these  specifications. 

Notice  of  rollhg  (24$)      No  material  shall  be  rolted  until  arrangements 

have  been  made  for  the  proper  testing  and  inspection  of  the 
same. 

Surface  (25°)      Kach  and  every  piece  of  material  shall  be  sub- 

Inspection 

-   nutted  to  examination   on  all  sides  and   for  that  purpose 

turned  over  when  required.  All  plates  shall  be  suspended 
for  examination  and  each  piece  shall  be  weighed  separately 
when  required  by  the  Inspector. 

Subsequent  (25:)     Acceptance  of  any  material  by  the   Inspector 

discovery      shall  not  prevent  its  subsequent  rejection  if  found  defective 
of  defects 

after  delivery,  and  such  material  shall  be  replaced  by  and 

at  the  expense  of  the  Contractor. 

(252)     Material,  when  examined  at  the  rolling  mills 
Mirks 

"  by  the  Inspector,  shall  when  found  acceptable,  be  stamped 

with  his  private  mark.  No  work  shall  be  done  upon  any 
material  that  does  not  bear  this  mark.  Small  bars,  rods, 


Facilities 


Full  size  tests 


MAINTE- 
NANCE 


First  Painting: 


Second 


Inspection 


etc.,  may  be  put  up  in  bandies  with  the  Inspector's  mark 
on  a  metal  tag  wired  to  the  same. 

(253)  All  facilities,   labor,  tools   and   instruments  ne- 
cessary for  the  inspection  and  testing  of  all'  material  in  ac- 
cordance with  the  letter  and  intent  of  these  specifications 
shall  be  furnished  free  of  expense  to  the  Railway  Company. 

(254)  Upon  request,   the   contractor  shall   be  advised 
as  to  the  number  of  pieces  required  for  full  size  tests. 

(255)  The  life  of  a  steel  bridge  depends  quite  largely 
upon  the  care  it  receives  and  in  view  of  this  fact  the  Author 
recommends. 

(256)  That  the  bridge  be  repainced  whenever  the 
final   coat  becomes  deteriorated   and   exposes   the   first 
field  coat  of  paint.    An  effort  should  be  made  to  at  all 
times  keep  the  first  field  coat  protected.    Before  repaint- 
ing all  surfaces  should  be  thorjughly   cleaned,  using 
wire  brushes  and  steel  scrapers  where  necessary.     The 
paint  used  should  be  the  same  as  thai  used  for  the  sec- 
ond field  coat.    A  marked  difference  in  the  colors  of  the 
first  and  second  field  coats  has  been  selected  in  order  to 
more  clearly  show  when  the  bridge  needs  painting. 

(257)  That   the   bridge   should   be   inspected   at 
frequent  intervals  by  some  competent  person  and  any 
necessary  repairs  be  made.    Especially  should  the  rivets 
in  the  floor  system  be  tested  and  if  any  are  found  loose 
cut  and  replace. 


—42— 


I 

APPENDIX. 


OF  THE 

UNIVERSITY 

OF 


—43- 


Table  giving  maximum  moments  (M)  and  end  reac- 
tions (R)  for  a  train  of  80000  pounds  street  cars  each  40 
feet  long  cen  er  to  center  of  couplings  and  upon  a  wheel 
base  of  5  plus  20  plus  5  equals  30  feet  and  the  values  of  \v 
based  upon  M  and  also  upon  R  where  the  equivalent  load  is 
"w  pounds  per  lineal  foot  uniformly  distributed  plus  10  w 
pounds  concentrated,  so  placed  as  to  give  the  maximum  effect 
in  every  case." 


Span 
in  feet 

M  in  foot  pounds. 

R  in  pounds 

W  has 

>ed  on 

M 

B 

10 

56250 

30000 

I5OO 

2OOO  | 

12 

75210 

31670 

^567 

J979  ! 

16 

II39IO 

35000 

1582 

J945 

2O 

I53I20 

4OOOO 

1531 

2OOO 

24 

211670 

46670 

1604 

2121  j 

28 

277820 

5H30 

1654 

2143  i 

32 

355600 

55000 

1701 

2H5  1 

36 

433800 

5778o 

1721 

2063  ' 

40 

512550 

60000 

1708 

2000  ! 

44     59^00 

63640 

1680 

1989  ; 

48     670400 

67920 

1643 

1998; 

52     749600 

7T93o 

I602 

1998  ! 

S6     850000 

75720 

1598 

J993  : 

60 

950000 

80000 

1583 

2OOO 

64    1070000 

83750 

!592 

1994  ! 

68 

II9OOOO 

89410 

1591 

2O32  i 

72 

I32OOOO 

93330 

1594 

2029 

76    1460000 

96850 

1601 

2018  1 

80 

lOOOOOO 

I  00000 

1600 

2000  i 

84 

1780000 

103800 

1630 

1997  ! 

88 

1960000 

107950 

1650 

J999  ; 

92 

2I5OOOO 

111950 

1661 

!999  ! 

96 

235OOOO 

117700 

1688 

2030 

IOO 

255OOOO 

I2OOOO 

1700 

2000 

105 

28OOOOO 

125720 

1707 

2OTO 

no    3050000 

130900 

1706 

2014  ' 

115    3400000 

135900 

1752 

2013  i 

1  20    3900000 

140000 

1857 

2OOO  • 

I25    3925ooo 

144800 

1732 

1997  ' 

150    5650000 

170700 

1773 

2008  1 

200   |   9950000 

22OOOO 

1809 

2000  1 

While  the  above  table  is  not  necessarily  exact,  it  is  close 
enough  to  illustrate  the  value  of  the  loadings  selected  in 
these  specifications. 


—44— 

Tab  e  giving  maximum  moments   (M)  and  end  reac- 
tions (R)  for  a  train  of  pressed  steel  cars  weighing  as  fol 
lows: 

Rated  capacity 100000  pounds 

Excess  load  10  per  cent 10000  pounds 

Weight  of  car 40000  pounds 

Total  load  for  each  car 1 50000  pounds 

each  car  having  a  length  of  32^  feet  center  to  center  of  coup- 
lings and  a  wheel  base  of  5  plus  15  plus  5  equals  25  feet,  and 
the  values  of  w  based  upon  M  and  also  upon  R  where  the- 
equivalent  load  is  "w  pounds  per  lineal  foot  uniformly  dis- 
tributed plus  10  w  pounds  concentrated  so  placed  as  to  give 
the  maximum  effect  in  every  case/' 


Span 
in  feet 

M  in  foot  pounds. 

R  in  pounds 

W  based  on 

M    |    R 

IO 

105400 

56250 

2812 

3750 

12 

I4IOOO 

59375    2938    3711  ; 

16 

254300 

71480    3532    3971 

2O 

328120 

84375 

3281      42l8 

24 

453  loo 

95312 

3432 

4332 

28 

600000 

103130 

3572 

4297 

32 

747700 

108980    3595  |  4191 

36 

895800 

117190 

3555 

4185 

40 

1044200 

126560 

348i 

4219 

44 

1162500 

i355io 

3303 

4235 

48 

1387500 

H53io 

340i 

4274 

52 

1612500 

155770 

3446 

4327 

56 

1846900 

166070 

3472 

4370 

60 

2132500 

175000 

3554 

4375 

64 

2428000 

182810 

3613 

4353 

68 

2690600 

191360 

3597 

4349 

72 

3028100 

200520    3657 

4360 

76 

3375000 

209700 

37oi 

4369 

80 

3750000 

219140 

3759 

4383 

84 

4162500 

229020 

3811 

4405 

88 

4575ooo 

239060 

3851 

4427 

92 

5006200 

248230 

3887    4433 

Q6 

5456200 

256640 

3920 

4425 

IOO 

5906200 

265310 

3938 

4422 

105 

6468800 

276790 

3943 

4429 

no 

7078100 

288070 

3960 

4432 

H5 

7687500 

300000 

396i 

4445 

1  20 

8343800 

312500 

3972 

4465 

125 

9421900 

324000 

4159 

4469 

150 

13078000 

381250 

4104    4486 

200 

23109000 

495940 

4202 

4508 

While  the  above  table  is  not  necessarily  exact,  it  is  close 
enough  to  illus  rate  the  value  of  the  loadings  selected  in  these 
specifications. 


—45— 

Table  giving  maximum  moments  (M)  and  end  reac- 
tions (R)  for  various  spans  for  E  40  loading  of  Theodore 
Cooper's  Specifications  and  the  values  of  "w"  based  on  M 
and  also  on  R  where  the  equivalent  load  is  "w  pounds  per 
lineal  foot  uniformly  distributed  plus  10  w  pounds  concen- 
trated ,  so  placed  as  to  give  the  maximum  effect  in  every 
case." 


Span 
in  feet 

M  in  foot  pounds. 

S  in  pounds 

W  oasea  on 

M|     S 

IO 

H25OO 

6OOOO 

3OOO      4OOO 

12 

160000 

70000    3333  I  4375  ! 

16 

280000 

85000 

3889 

4722 

2O   |     412500 

100000    4125  |  5000  1 

24 

570400 

110800    4321 

5036  ! 

28 

731000 

120800 

4351 

5033 

32 

9IO8OO 

131500 

4379 

5058 

36 

IO97OOO 

141100 

4354 

5040  I 

40 

I3IIOOO 

150800 

4370 

5027 

44  |   1543000 

161100 

4384 

5034 

48 

I  7/6OOO 

16(3600 

4353 

4989 

52     2030000 

178500 

4338 

4959 

56     2304030 

186000 

4331 

4895 

60     2599000 

195200 

4332 

4880  : 

64 

29IIOOO 

205200 

4332 

4886 

68 

3247000 

215600 

434i 

4900 

72 

3584000 

226700 

4339 

4929  ! 

76 

3942000 

238100 

4323 

4961   ' 

So 

4321000 

248400 

4321 

4968 

84 

4713000 

259000 

43*6 

4081 

88 

5I28OOO 

269400 

4317    49?9  i 

92 

5552000 

279600 

43H 

4993 

96 

5988000 

289600 

4302 

4994 

IOO 

6440000 

300000 

4293 

5000  ; 

105 

7075000 

312200 

43T2 

4994 

no 

7774000 

324000 

4349 

4985 

"5 

8490000 

3358oo 

4375    4975 

1  20 

9228000 

347400 

4394    403 

125 

9993000 

358800 

4411    4050 

150 

I4II2OOO 

414670 

4428 

4879 

200 

237I2OOO 

522000 

4312 

4745 

Load  equivalent  to  E  40  equals,  say  5000  pounds  uniform 
plus  50000  pounds  concentrated,  based  on  R  and  4500  pounds 
uniform  plus  45000  pounds  concentrated,  based  on  M. 


-46— 

Table  giving  a  comparison  between  the  loads  used  111 
these  specifications  and  the  tpyical  loads  shown  in  Theodore 
Cooper's  Specifications: 

L  20        equals  E  16  (2-  56.8  ton  engines  followed  by  1600- 
pounds  per  lineal  foot.) 

L  30       equals  £24   (2-  85.2  ton  engines  followed  by  2400 
pounds  per  lineal  foot.) 

1^37-5     equals  £30   (2-106.5  ton  engines  followed  by  3000 
pounds  per  lineal  foot.) 

L4O        equals  £32   (2-113.5  ton  engines  followed  by  3200 
,  ,  pounds  per  lineal  foot.) 

L  43.75  equals  £35   (2-124.2  ton  engines  followed  by  3500 
pounds  per  lineal  foot.) 

L  50        equals  E  40   (2-142.0  ton  engines  followed  by  4000 
pounds  per  lineal  foot.) 

L  60    -    equals  £48   (2-170.4  ton  engines  followed  by  4800 
pounds  £er  lineal  foot.) 

L62.5     equals  E  50   (2-177.5  ton  engines  followed  by  5000 
pounds  per  lineal  foot.) 


CURVES  /LLU37~ffAT/N6    VAL 

^°°       US££>  //V  UN/r  S77?£5S  /CV?/1 
^       fr/n  Stress 

U£5      I  

ruLA£  :  —  :  :  "  : 

ft 

1  50 
ISO 
J70 

6- 

9' 

flax  Sfress 
Dead  Load  5fn 
flax  Sfress 

*S5 

—  7  ~  ~i  — 

Sta*  J7 

rm 

Of  <5r(. 

'&fer, 

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V  / 

J     £        -     _ 

J6O 

7                  ^ 

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J4-O 

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7     ~ 

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p> 

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~: 

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,0or  <?*        O 


O.Z 


O--5 


07     o&      oe> 


SHEA  /?//V<5  STR£5S 
//V     LATE6/PDEF    WEBS 
W/THOUT 


SPECIFICATIONS 


FOR  BRIDGE 


AT- 


FOR 


GENERAL  SPECIFICATIONS 


FOR 


RAILWAY  BRIDGE  SUPERSTRUCTURE 


THE  OSBORN  ENGINEERING  Co 

OSBORN  BUILDING, 
CLEVELAND,     -     OHIO. 


I9O3. 


TABLE  OF  CONTENTS. 


PARA- 
GRAPHS. 

I.  CLEARANCE                 .         ......  i 

II.  DRAWINGS        ........  2-12 

III.  FLOOR             .........  I3.l8 

IV  LOADS        .........  I9.30 

V.  UNIT  STRESSES  .......     3I_4I 

VI.  GENERAL  DETAILS        .         .        ....        42-69 

VII.  I  BEAM  SPANS      ........     7o_7I 

VIII.  PLATE  GIRDERS      ..-»....         72-83 

IX.  STRINGERS  AND  FLOORBEAMS     ....     84-88 
X  TRUSSES  AND  TOWERS         .         .      .  .        .         .89-104 

XI.  RIVETED  WORK          .;....          105-114 

XII.  QUALITY  OF  MATERIALS  : 

A.  -Wrought  Iron         ......       115-123 

B.-Cast  Iron     ........         I24 

c.-Wrought  Steel        ......       125-141 

D.-Cast  Steel  .......         I42 


143-151 


F.-Tiraber        ........         I52 

XIII.      WORKMANSHIP      .....         .  153-157 

XIV       INSPECTION  AND  TESTS         ....          158-161 

XV.  ERECTION        .......  162-172 

XVI.  NAME  PLATES     .......  I?3 

XVII.  GENERA!  .....  . 


SPECIFICATIONS. 


BRIDGE  OVER. 

at.... 


The  engineer's  general  drawings  consist  of: — 


The  Superstructure  will  consist  of spans long. 

Live  load  to  be..., 


Paint  ' 'first  coaV '  to  be  .... 

"finish  coats"  to  be. 

Contractor  to  erect 


The  entire  work  to  be  completed  on  or  before 79. 

Traffic  to  be  maintained 


Old  Structure  to  be  removed. 


C  Contractor  to  furnish  falsework  timber 

"       "        and  place  wooden  floor. 


(3) 


GENERAL  SPECIFICATIONS 


FOR 

Railway  Bridge  Superstructures 


THE  OSBORN  ENGINEERING  COMPANY 
Osborn  Building.  Cleveland,  O. 


1903. 


I.  CLEARANCE. 

1.  On  a  straight  track  a  section,  as  per  diagram  given  in 
appendix,    must   be   kept   clear   in    single    track    through 
bridges.     On  a  curved  track  and  in  double  track  structures 
the  clear  width   must  be  proportionately   increased.      The 
distance  center  to  center  of  the  double  track  is  13  feet.    As- 
suming length  of  cars  75  feet  and  spacing  of  trucks  54  feet, 
center  to  center,  2^  inches  additional  clear  width  must  be 
provided  on  the  inside. of  curves  for  every  inch  of  elevation 
of  outer  rail,  on  account  of  tipping  of  cars.     The  width 
from  center  to  center  of  trusses  shall  not  be  less  than  i-2oth 
of  the  span. 

See  Appendix  A. 

II.  DRAWINGS. 

2.  Accompanying   these    specifications,    and    forming   a 
part  hereof,  are  general  drawings,  as  enumerated  on  the 
second  page  of  these  specifications,  embodying  the  infor- 
mation and  data  furnished  the  contractor  for  his  guidance. 

3.  If  general  drawings  are  submitted  by  the  contractor 
with  his  proposal,  they  shall  include  all  stress  sheets  giving 
the  lengths  of  spans  from  center  to  center  of  chords;  the 
width  of  the  bridge  in  the  clear  and  from  center  to  center 

(5) 


Engineer's 

General 

Drawings. 


Contractor's 

General 

Drawings. 


Shop  Drawings. 


Drawings. 


Shop  and 
Order  Bills. 


Size  of 
Drawings. 


of  trusses;  the  dead,  live  and  other  loads  on  which  calcu- 
lations are  based;  the  dead,  live  and  other  load  stresses  as 
well  as  the  minimum  stresses,  and  sections  for  all  mem- 
bers; the  sections  and  areas  of  lateral  and  portal  struts, 
lateral  and  sway  rods  or  angles ;  stringers,  floor-beams  and 
their  connections;  sizes  of  rivets;  size,  arrangement  and 
character  of  floor  system ;  and  the  class  or  classes  of  ma- 
terial proposed  for  use  in  the  various  parts  of  the  structure. 

The  dead  loads  assumed  for.  calculating  the  stresses  shall 
not  be  less  than  the  actual  weight  of  the  structure. 

The  plus  (-)-)  sign  shall  be  used  to  indicate  compression 
stresses  and  the  minus  ( — )  sign  to  indicate  tension  stresses. 

Stresses  shall  be  given  in  pounds,  and  weights  of  shape 
metal  in  pounds  per  foot  of  one  piece, 

The  plans  shall  also  include  such  detail  drawings  as  are 
necessary  to  express  the  general  intent  of  the  whole  work. 

4.  The  contractor  shall  not,  except  at  his  own  risk,  or- 
der any  material  until  after  the  shop  drawings  have  been 
approved  by  the  engineer.     After  approval,  the  contractor 
shall  furnish  the  engineer,  without  charge,  as  many  sets  of 
the  shop  drawings  as  he  may  require. 

5.  After  the  award  of  the  contract,  two  complete  sets 
of  drawings  and  details,   including  stress   sheet   described 
above  shall  be  furnished  for  approval,  one  set  of  approved 
drawings  will  be  returned  to  the  contractor  and  one  will  be 
retained  by  the  Railway  Company.     One  or  more  sets  of 
drawings  may  also  be  required  for  the  use  of  the  inspector. 
These  drawings  shall  in  general  be  drawn  to  a  scale  of  one 
inch  to  the  foot. 

6.  The  contractor  shall  also  furnish  the  engineer  with 
duplicate  copies  of  all  shop  and  order  bills  of  material  and 
shipping   lists   of   all   finished   parts,    with    exact   itemized 
weights  of  same. 

7.  All  drawings  shall  be  of  uniform  size  twenty-four  by 
thirty-six    inches    (24"x  36").      They    shall    be   numbered, 
arranged  in  systematic  order  and  indexed. 


(6) 


8.  On  all  drawings,   dimensions   shown   in  figure  shall 
govern  in  cases  of  discrepancy  between  scale  and  figures. 

9.  The  contractor  shall  check  all  leading  dimensions  and 
clearances  as  a  whole  and  in  detail,  the  fitting  of  all  details, 
and  becomes  responsible  for  the  exact  position  and  elevation 
of  all  parts  of  the  work ;  and  the  approval  of  the  working 
drawings  by  the  engineer  shall  not  relieve  the  contractor  of 
this  responsibility. 

10.  In  constructing  the  work,  no  variations  at  any  time 
from  the  approved  drawings,  nor  from  these  specifications, 
shall  be  made  by  the  contractor,  without  a  written  order 
from  the  engineer  in  each  case,   describing  and   directing 
such  change. 

11.  Notes  or  specifications  appearing  on  the  engineer's 
general  drawings  are  to  be  construed  as  superseding  and 
voiding  any  clauses,  or  parts  of  clauses,  in  these  specifica- 
tions, with  which  they  may  conflict. 

12.  Rivets    shall   be   indicated   in   accordance   with   the 
code  shown  in  the  appendix. 

See  Appendix  B. 

III.  FLOOR. 

13.  Cross-ties  shall  be  of  the  best  quality  of  long  leaf 
southern  yellow  pine,  white  or  burr  oak.     They  shall  have 
a  width  of  8"  and  a  depth  depending  upon  the  distance  be- 
tween centers  of  supports,  as  follows : 

Spans. 

to      c.     Dimensions. 


Up  to 


7-0 

7'-o" 

8'-o" 

9'-o" 

10  '-o" 

12  '-O" 


8  X   8  XIO-O 

8"x  9"xio'-o" 
8"xio"xio'-o" 
8"xii"xi2'-o" 

8"XI2"XI2'-0" 

8"xi4"xi4'-o" 

They  shall  be  spaced  12"  between  centers,  notched  y2'f 
over  supports,  and  every  fourth  tie  shall  be  fastened  to  the 
Manges  of  stringers  by  y^"  hook  bolts  flattened  at  their 


Dimensions. 


Contractor 
Responsible 
for  Accuracy. 


Variations. 


Notes. 


Rivets. 


Cross-ties. 


(7) 


Ribbons. 


Deck  Bridges. 


Elevation  of 
Outer  Rail. 


lower   ends    to   prevent   turning.      These   bolts    shall    pass 
through  the  raising  pieces  when  used,  if  practicable. 

14.  There  shall  be  an  8"x6"  ribbon,  of  the  same  material 
as  the  ties,  on  each  side  of  each  track,  with  its  inner  face 
parallel  to  and  not  less  than  4'  2"  from  the  center  of  the 
track  and  notched  i-%"  over  each  tie,  when  rails  5"  high 
are  used.     When  rails  of  less  height  than  5"  are  used,  the 
ribbon  shall  be  notched  so  that  its  upper  surface  shall  be 
y2"  below  the  top  of  the  rail,  or  a  ribbon  of  less  height 
may  be  used. 

The  ribbon  shall  be  fastened  to  every  fourth  tie  (using 
the  ties  secured  to  the  stringers  by  hook  bolts)  by  ^T  ma- 
chine bolts,  having  a  y%"  wrought  washer  on  the  top  of  the 
ribbon,  and  a  *^"  cast  washer  under  the  tie.  Ribbons  shall 
be  spliced  over  ties  by  halving  horizontally  with  a  lap  of  6" 
Each  splice  shall  be  secured  by  a  yfa"  bolt  at  center,  the 
holes  of  the  bolts  being  11-16"  in  diameter.  The  ribbons 
must  be  continued  over  all  piers  and  abutments. 

15.  Hook  bolts  and  ribbon  bolts  are  considered  to  be 
a  part  of  the  metal  superstructure.     See  paragraph  163. 

16.  The   standard  spacing  for  track   stringers   shall  be 
6'-6"  between  centers,  and  the  tracks  will  be  i3'-o"  between 
centers  unless  otherwise  ordered.     In  double  track  metal 
bridges  with  three  trusses  the  clearance,   length   of  cross 
ties  and  spacing  of  stringers   for  each  track  shall  be  the 
same  as  above  specified  for  single  track  bridges. 

17.  In  single  track  metal  bridges,  if  the  width  between 
centers  of  trusses  does  not  exceed  12'  the  cross  ties  may 
rest  directly  on  the  top  chords.     If  of  greater  width,  floor 
beams  and  track  stringers  shall  be  used.     In  plate  girders 
having  a  span  of  5o'-o"  or  less,  the  girders  shall  be  6'-6"  c. 
to  c.  and  in  longer  spans  8'-o"  c.  to  c.     All  girders  shall  be 

.thoroughly  braced  laterally  and  transversely. 

18.  The  outside  rail  shall  be  elevated  as  required  by  the 
engineer.     This  will  be  effected  by  wedge-shaped  ties  or 

(8) 


by  raising  pieces  on  supports  as  may  be  deemed  best.  If 
wedge-shaped  ties  are  used,  their  depth  at  the  inner  sup- 
port shall  not  be  less  than  for  bridges  on  tangent. 


IV.  LOADS. 

19.  The   weights   assumed    for   calculation   shall   be   as 
follows :     Rails  and  fastenings   100  Ibs.  per  lineal  foot  of 
track.    Timber  per  foot  B.  M.,  Oak,  4-^  Ibs. ;  Yellow  Pine, 
4  Ibs.;  Wrought  Iron,  31-3  Ibs.  per  lineal  foot  for  bar  i" 
square.     Wrought  Steel,  3.4  Ibs.  per  lineal  foot  for  bar  i" 
square.     The  dead  load  shall  be  assumed  as  concentrated 
2-3  at  panel  points  of  loaded  chord,  and  1-3  at  panel  points 
of  unloaded  chord. 

20.  The  moving  load  shall,  unless  otherwise  specified,  be 
one  of  the  loadings  given  in  appendix,  and  specified  on  the 
second  page  hereof. 

See  Appendix  C. 

21.  The  effect  of  impact  and  vibration  shall  be  added  to 
the   maximum   strains   resulting    from   the   live   load,   and 
shall  be  determined  by  the  following  formula : 


L 


=  L 


L  +  D 

Where  I  =  Impact. 

L  —  Maximum  live  load  stress. 

D  =  Dead  load  stress. 

The  impact  on  floor  beam  hangers  shall  be  assumed  at 

125%. 

In  computing  the  effect  of  impact  in  cases  where  the  live 
load  and  dead  load  stresses  are  of  opposite  nature,  the  dead 
load  stress  shall  be  assumed  to  be  zero. 

22.  Where  the  structure  is  on  a  curve,  the  effect  of  cen- 
trifugal force  shall  be  considered  and  computed  by  the  fol- 
lowing formula : 


(9) 


Static  Load. 


Moving  Load. 


Impact. 


Centrifugal 
Force. 


Longitudinal 
Forces. 


Wind  Forces. 


Trestles. 


W  V2 

32,  2,  r. 
In  which  W  —  Live  Load, 

—  Velocity  in  feet  per  second, 
=  Radius  of  curve  in  feet, 

Note. — See  Osborn's  Tables  for  values  of  C  for  various 
velocities  and  degrees  of  Curvature. 

23.  The  longitudinal  bracing   in  metal  towers  and  the 
attachments  of  fixed  ends  of  all  girders  shall  be  capable  of 
resisting  the  momentum  of  train  when  brought  to  a  sudden 
stop,  the  co-efficient  of  friction  of  wheels  sliding  upon  rails, 
being  assumed  at  0.2. 

24.  The   bottom   lateral   bracing   in    deck   truss   bridges 
and  the  top  lateral  bracing  in  through  truss  bridges  shall  be 
proportioned  to  resist  a  moving  force  of  150  Ibs.  per  lineal 
foot  for  spans  of  200  feet  and  under,  and  0.4  Ibs.  per  lineal 
foot  for  each  additional  foot  in  length  over  200  feet. 

25.  The  bottom  lateral  bracing  in  through  truss  bridges 
and  the  top  lateral  bracing  in  deck  truss  bridges  shall  be 
proportioned  to  resist  a  moving  force  of  450  Ibs.  per  lineal 
foot  for  spans  of  200  feet  and  under,  and  0.4  Ibs.  per  lineal 
foot  for  each  additional  foot  in  length  over  200  feet. 

26.  The  lateral  bracing  in  plate  girder  bridges  shall  be 
proportioned  to  sustain  a  moving  load  of  330  Ibs.  per  foot 
with  30  Ibs.  additional  for  each  foot  in  depth  of  girder.  Rigid 
cross   frames  shall  be  provided  connecting  the  upper  and 
lower  flanges  at  intervals  not  exceeding  fifteen  feet,  and  all 
bracing   shall   be   capable   of   transmitting   compression    as 
well  as  tension  stresses.     The  lateral  bracing  in  deck  plate 
girder  bridges   will   be  placed   in   the   plane  of   the   upper 
flanges. 

27.  In  trestle  towers,  the  bracing  and  posts  shall  be  pro- 
portioned to  resist  wind  pressures  in  addition  to  the  stresses 
from  dead  load,  live  load,  centrifugal  and  traction  forces,  as 
follows : 


(10) 


ist.  A  force  of  300  Ibs.  per  lineal  foot  of  structure  ap- 
plied 8'  above  base  of  rail,  and  a  wind  pressure  of  30  Ibs. 
per  sq.  ft.  on  the  exposed  surfaces  of  all  trusses,  girders 
and  towers. 

2nd.  A  wind  pressure  of  50  Ibs.  per  sq.  ft.  on  the  ex- 
posed surfaces  of  all  trusses,  girders  and  towers. 

All  trestle  bracing  shall  preferably  be  composed  of  shapes 
designed  to  transmit  compression  as  well  as  tension  stresses. 

28.  In  determining  anchorage  for  the  loaded  structure, 
the  trains   shall  be  assumed  to   weigh  800   Ibs.   per  lineal 
foot. 

29.  Lateral  and  longitudinal  struts  shall  be  proportioned 
to  resist  the  resultant  due  to  an  initial  stress  of  10,000  Ibs. 
per  square  inch  upon  all  rods  attached  to  them  when  this  is 
in  excess  of  wind  stress. 

30.  Where  the  effect  of  a  variation  of  150  degrees  F.  is 
to  produce  stresses  in  the  structure,  the  maximum  of  such 
stresses  in  each  member  shall  be  provided  for. 


Anchorage 


Struts. 


Temperature 
Stresses. 


V.  UNIT   STRESSES. 

31.     All  parts  of  the  structure  shall  be  proportioned  by 
the  following  unit  stresses:     (See  paragraph  21.) 

Wrought  iron,  13,000  Ibs.  per  square  inch. 
Soft  steel,  15,000  Ibs.  per  square  inch. 
Medium  steel,   17,000  Ibs.  per  square  inch. 


Tension. 


32.     Members  with  square  C 

bearings  at  both  ends,  I2 


per  Sq.   inch.  Compression. 


36,000 


Members  with  square     C 

bearings  at  one  end  f         per  sq.  inch. 

and  pin  bearings  at        1-| 

the  other,  24,000  f 

(ii) 


Members  with  pin  bear- 
ing's at  both  ends, 


Bending. 


Bearing. 


Shearing. 


Field  Rivets. 


Wind  Stresses. 


Alternate 
Stresses. 


per  sq.  inch, 


18,000  r~ 

In  which  0=13,000  for  wrought  iron. 
0=  15,000    "     soft  steel. 
0=17,000    "     medium  steel. 
1  —  length  between  supports  in  inches, 
r  =  least  radius  of  gyration  in  inches. 
1/r  shall  not  exceed        100  for  main  members  and 

1 20  for  subordinate  mem- 
bers. 

72 

NOTE. — Values  of    2  may  be  taken  from  Osborn's  Tables. 

33.  Pins,  closely  packed,  medium  steel,  25,000  Ibs.  per 
square  inch. 

34.  Pins  22,000  Ibs.  per  square  inch. 

Rivets  20,000  Ibs.  per  square  inch. 

35.  Pins,  medium  steel 11,000  Ibs.  per  square  inch. 

"  Rivets 10,000  Ibs.  per  square  inch 

On  webs  of  plate  girders  soft  steel.  .  9,000  Ibs. 

Medium  steel .  .  .  10,000  Ibs. 

36.  The  number  of  rivets  thus  found  shall  be  increased 
20$  for  rivets  driven  in  field. 

37.  The  same  permissible  stress  shall  also  be  used  for 
members   subject   to   wind   stresses,   centrifugal   force  and 
momentum  of  train.     No  allowance  will  be  made  for  the 
wind  stress  when  combined  with  stress  from  dead  and  live 
load,  unless  the  combined  stress  exceed  by  25  per  cent,  the 
stress   from   dead   and   live   load   only,   in   which   case  the 
combined  stress  will  be  used  with  a  unit  stress  25  per  cent, 
greater  than  above  given. 

38.  Members  subject  to  alternate  stresses  of  tension  and 
compression  in  immediate  succession,   shall  be  so  propor- 
tioned that  the  total  sectional  area  is  equal  to  the  sum  of 
the  areas  required  for  each  stress.      (See  paragraph  21). 

The  strength  of  the  connections  shall  be  proportionately 
increased. 


(12) 


39-  Members  subjected  to  combined  bending  and  direct 
stresses  must  be  proportioned  for  the  combined  stresses. 

40.  The  timber  parts  of  the  structure  shall  be  propor- 
tioned by  the  following  unit  stresses,  given  in  pounds  per 
square  inch. 


SPECIES 

Trans- 
verse 
Loading-. 

End 
Bearing1. 

Short  Col- 
umns 1 
equai  to  or 
less  than 
12  d. 

Bearing 
Across 
Fibre. 

Shear 
Along 
Fibre 

i  .    \Yhite  Oak 

1400 

1400 

IOOO 

600 

300 

2.    L/ong  Leaf  Pine 

1600 

1600 

IOOO 

350 

200 

3.    White  Pine 

IOOO 

ICOO 

700 

200 

150 

41.     Columns  whose  length  exceeds  12  times  their  least 
side  shall  be  proportioned  by  the  following  formula : 

C  . 

p 


Combined 
Stress. 


Timber. 


Timber 
Columns. 


1,000  d2 

Where  P=  Unit  load  on  column. 

C=  Unit  load  as  given  above  for  short  columns. 

1=  Length   of    column    between    supports,     in 
inches. 

d=  Least  side  of  column,  in  inches. 

VI.  GENERAL   DETAILS. 

42.     When  the  track  is  on  a  curve,  both  inner  and  outer        Track  on 
trusses  or  girders  are  to  be  alike  and  to  be  figured  for  the        Curve' 
proportion  of  the  live  load  given  by  the  formula: 

m  +  b 


w  = 


2b 


Where 

W  ±=  load  going  to  either  trusses. 

m  =  center  ordinate  to  curve. 

b  =  width  c.  to  c.  of  trusses. 

P  =  the  live  load  at  panel  point  considered. 


(13) 


Net  Section. 


Pins  and 
Rivets. 


Effective 
Diameter 
of  Rivets. 


Minimum 
Number  of 
Rivets. 

Pitch  of  Rivets. 


Distance  from 
Center  of  Rivet 
to  Edge  of 
Plate. 


Distance 
Between  Rivets 
in  Compression 
Members. 


Rotters. 


43.  The  net  section  of  any  tension  member  or   flange 
shall  be  determined  by  a  plane,  cutting  the  member  square 
across  at  any  point.     The  greatest  number  of  rivet  holes 
which  can  be  cut  by  this  plane,  or  come  within  an  inch  of 
it,  are  to  be  deducted  from  the  gross  section. 

44.  In  deducting  rivet  holes  to  obtain  the  net  section  of 
riveted  tension  members,  the  rivet  hole  shall  be  taken  with  a 
diameter  one-eighth    (% )    inch  larger  than  the   undriven 
rivet  for  rivets  with  full  heads,  and  one-fourth   (*4)   inch 
larger    for   countersunk    rivets     in    plates    ^g"    or    less    in 
thickness. 

45.  The  effective  diameter  of  the  driven  rivet  shall  be 
assumed  the  same  as  its  diameter  before  driving. 

46.  Where   rivets   are   countersunk   the   bearing  of   the 
head  shall  not  be  counted. 

47.  No  connection  shall  be  made  with  less  than  three 

(3)  rivets. 

48.  •  The  pitch  of  rivets  shall  not  exceed  6  inches,  nor 
be  less  than  three  diameters  of  the  rivet.  At  the  ends  of 
compression  members  the  pitch  shall  not  exceed  four  diam- 
eters of  the  rivet  for  a  length  equal  to  twice  the  depth  of 
the  member,  and  in  the  flanges  of  girders  and  chords  carry-  ' 
ing  floor  the  pitch  shall  not  exceed  4  inches. 

49.  The  distance  from  center  of  rivet  to  edge  of  plate 
shall  not  be  less  than   i-%   inches,  except  in  bars  under 
2.-V-2  inches  wide.    When  practicable  it  shall  be  at  least  two 
diameters  of  the  rivet:     It  shall  not  exceed  eight  times  the 

thickness  of  the  plate. 
i 

50.  The  distance  between  rivets   for  plates  strained  in 

compression  shall  not  exceed  sixteen  times  the  thickness  of 
plate  in  line  of  stress,  nor  forty  times  the  thickness  at  right 
angles  to  line  of  stress. 

51.  All  bridges  exceeding  80  feet  in  length  shall  have 
hinged  bolsters  at  each  end  and  at  one  end  nests  of  turned 
friction  rollers  of  steel  bearing  upon  planed  surfaces.     The 
rollers  shall  not  be  less  than  4"  in  diameter,  and  the  pres- 


(14) 


58.  Heads  of  eye  bars  shall  be  so  proportioned  as  to 
develop  the  full  strength  of  the  bar.  The  heads  shall  be 
formed  by  upsetting-  and  forging,  and  in  no  case  will  weld- 
ing be  allowed.  (See  paragraph  101.) 

(15) 


Least  Thick- 
ness of  Plates. 


Length  of 

Compression 

Members. 


sure  per  lineal  inch  of  roller  shall  not  exceed  500  times  the 
diameter  of  roller  in  inches.  For  bridges  under  80  feet 
in  length,  one  end  shall  be  free  to  move  upon  planed  sur- 
faces. 

52.  No  plate  or  shape  shall  be  less  than  ^  inch  thick  for 
main  members,  or  5-16  inch  thick  for  wind  bracing,  lattice 
bars,  etc. 

53.  Compression   members    shall   not   exceed   in   length 
40  times  their  least  width  nor  100  times  the  least  radius  of 
gyration  tor  main  members,  and  120  times  the  least  radius 
of  gyration  for  subordinate  members.     "Main  Members" 
shall  include  all  elements  of  trusses,   posts  of  towers  or 
bents,  and  all  other  members  directly  acted  upon  by  the  live 
load.    "Subordinate  Members"  shall  include  lateral  systems, 
sway  bracing,   and   all   other  members   not   directly   acted 
upon  by  the  live  load. 

54.  The   several   segments    or   parts   of   a   compression 
member  shall  be  proportionately  as  strong  as  the  member 
taken  as  a  whole. 

55.  Stay  plates  shall  have  a  thickness  of  not  less  than 
one-fortieth  (1-40)  the  unsupported  width.     They  shall  be 
not  less  than  twelve    (12)   inches  long,  nor  less  than  the 
greatest  width  of  the  member.     "By  length  of  stay  plate  is 
meant  the  dimension  parallel  to  the  axis  of  the  member." 

56.  Lacing  shall  never  make  an  angle  of  less  than  60° 
with  the  axis  of  the  member.     If  clear  width  between  seg- 
ments exceed   12  inches  the  member  shall  be  double  lat- 
ticed, and  the  latticing  shall  never  make  an  angle  of  less 
than  45°  with  the  axis  of  the  member. 

57.  Long  vertical   tension   members   will   preferably  be        Tension 

..-          ,  Members. 

stiffened. 


Stay  Plates 


Lacing. 


Eye  Bars. 


OF  T 


UNIVEP:. 

• 

.-.-..  _K,\ 


Riveted  Tension 

Members. 


Rods. 


Loop  Eyes. 


Area  of  Rods. 


Screw  Ends 


Washers  and 
Nuts. 


Bolts. 


59.  Eye  bars  must  be  perfectly  straight  before  boring 
and  bars  working  together  shall  be  piled  and  clamped  to- 
gether and  bored  in  one  operation. 

60.  Eye  bars  shall  not  be  less  than  five-eighths  (  y& )  inch 
thick,  and  preferably  not  less  than  one-fifth  (1-5)  the  width 
of  the  bar. 

61.  Riveted  tension  members   shall  have  an   excess   of 
section  of  twenty-five  (25)  per  cent,  through  pin  holes  and 
net  section  at  all  other  points.     Pin  plates  shall  also  be  pro- 
portioned for  bearing  on  pins.     The  material  back  of  pins 
shall  be  proportioned  for  double  shear,  using  for  working 
length  the  distance  from  back  of  pin  to  end  of  plate.     But 
the  length  of  plate  back  of  pin  shall  not  be  less  than  two  and 
one-half  (2^2)  inches. 

62.  All  rods  with  screw  ends  shall  be  upset  at  the  ends 
so  that  the  area  at  the  root  of  the  thread  shall  exceed  by 
seventeen  (17)  per  cent,  the  area  of  the  rod. 

63.-.  All  rods  with  welded  heads  must  be  of   wrought 
iron. 

64.  When  loop  eyes  are  used,  the  loop  must  be  so  de- 
signed as  to  develop  the  full  strength  of  the  bar. 

The  eyes  must  be  reamed,  and  give  full  bearing  on  the 
pins. 

65.  No  lateral  or  diagonal   rod  shall  be  less  than  one 
square  inch  in  area. 

66.  Screw  threads  shall  be  cut  according  to  U.  S.  stand- 
ard, except  in  ends  of  pins. 

67.  Washers   and   nuts   shall   have   a   uniform   bearing. 
All  nuts  shall  be  easily  accessible  with  a  wrench   for  the 
purpose   of   adjustment,   and   shall   be   effectively    checked 
after  the  final  adjustment.     All  parts  working  together  or 
parts  of  one  member  of  the  truss  must  be  equally  strained. 

68.  All  bolts  must  be  of  neat  length  and  have  a  washer 
under  head  and  nut  when  they  are  in  contact  with  wood. 
\Yashers  and  nuts  shall  have  a  uniform  bearing.     All  nuts 


(16) 


shall  be  easily  accessible  with  a  wrench  for  the  purpose  of 
adjustment,  and  shall  be  effectively  checked  after  the  final 
adjustment. 

Rivets  shall  be  used  in  preference  to  bolts  to  resist  shear- 
ing stresses. 

When  bolts  are  unavoidable  they  must  be  turned  to  a 
driving  fit  and  have  a  washer  under  each  and  every  nut. 
Bearing  on  threads  will  not  be  allowed. 

Bolts  with  hexagonal  nuts  shall  in  general  be  used,  and 
round-headed  bolts  will  not  be  allowed. 

69.     All  spaces  which  would  otherwise  permit  the  lodg-        Drainage, 
ment  of  water  mifst  be  drained  or  filled  with  water-proof 
material. 


VII.  I    BEAMS. 

70.  I  beams  will  be  connected  together  in  groups  of  two 
or  three  for  each  rail,  have  a  y^  inch  sole  plate  and   ^ 
inch  bed  plate  at  each  end,  and  be  secured  at  each  end  to 
masonry  by  two  i"  anchor  bolts,  which  shall  enter  the  ma- 
sonry at  least  9   inches.     Sheet   lead   y%   inch  thick  to  be 
shipped,  boxed,  with  girders  and  to  be  placed  between  bed 
plates  and  masonry.    When  ends  rest  on  timber  wall  plates, 
the  loose  bed  plate  can  be  omitted. 

71.  When  two  or  three  "I"  beams  form  a  compound 
girder  they  will  be  connected  together  at  intervals  of  about 
3  feet,  by  means  of  vertical  I  beam  separators  riveted  to 
their  webs. 

The  standard  width  center  to  center  of  "I"  girders  will 
be  4  feet  n  inches  and  I  beam  separators  will  be  not  less 
than  20"  deep  when  two  beams  are  used,  and  10"  deep 
when  three  beams  are  used. 

There  will  be  a  strut  at  each  end,  and  a  system  of  angle 
bracing  between  the  girders. 


VIII.  PLATE    GIRDERS. 

Calculation.  72.     The  length  of  the  span  shall  be  considered  as  the 

distance  between  centers  of  end  bearings,  and  the  depth 
which  shall  preferably  be  not  less  than  i-io  of  the  span, 
shall  be  taken  as  the  distance  between  centers  of  gravity  of 
the  flanges,  unless  this  exceeds  the  depth  from  back  to  back 
of  angles,  in  which  case  this  latter  depth  shall  be  taken. 

Flanges.  73-     The  compression  flanges  of  plate  girders  and  beams 

shall  be  made  of  the  same  gross  section  as  the  tension 
flanges,  and  they  shall  be  stayed  transversely  when  their 
length  is  more  than  twenty  times  their  width. 

webs.  74-     One-sixth   of  the  web  may  only  be  considered  as 

available  gross  area  in  each  flange  when  the  web  sheet  is 
not  spliced.  All  joints  shall  be  spliced  by  a  plate  on  each 
side  of  the  web  and  these  plates  shall  have  a  double  line 
of  rivets  on  each  side  of  the  joint. 

stiffeners.  75-     All  web  plates  shall  be  stiffened  at  both  edges  of 

end  bearings,  and  at  all  points  of  local  concentrated  load- 
ings. Intermediate  stiffeners  shall  be  used  if  the  ratio  of 
unsupported  depth  of  web  to  the  thickness  is  greater  than 
fifty. 

76.  Stiffeners  shall  be  in  pairs,  and  spaced  so  the  shear 
per  foot  shall  not  exceed  the  safe  shear  given  by  the 
formula. 

20000  x  12  t 


soco  r 

Where  t  =  the  thickness  of  web  plate  in  inches 

d  =  the  clear  distances  between  supports  in  inches. 
NOTE. —  See  Osborn's  Tables  for  safe  resistance  of  web 
plate  against  buckling. 

The   maximum   spacing  of   stifleners  shall  not  exceed 
six  (6)  feet. 

77.     There  shall  be  at  least  two  pair  of  stiffeners  over  the 
end  bearings,  the  projecting  legs  of  which  shall  be  as  wide 

(18) 


as  flange  angles  will  permit.     These  four  stiffeners,  includ- 
ing their  fillers,  shall  take  care  of  the  maximum  end  shear. 

78.  Intermediate  stiffeners  shall  not  be  less  than  given 
below : 

For  Webs  4  feet  and  under 3^2  x  3  x  5-16 

For  Webs  4  feet  to  7  feet 3>4  x  3^  x  ^ 

For  Webs  over  7  feet ,  5  x  3^  x  ^ 

79.  Fillers,  unless  ruled  otherwise  for  special  cases,  shall        Fillers, 
be  placed  under  all  stiffeners,  the  thickness  being  equal  to 

the  thickness  of  the  flange  angles. 

80.  Six  inch  legs  and  over  will  in  all  cases  be  connected 
to  the  web  plates  by  two  rows  of  staggered  rivets,  the  pitch 
of  rivets  shall  not  be  less  than  2-^4"  nor  more  than  4-^2". 

81.  Not  less  than  one-half  the  total  area  of  the  flanges 
shall  be  concentrated  in  the  angles,  or  the  largest  size  angles 
shall  be  used. 

82.  Through   plate  girders   or  lattice   girders    shall  be 
stayed  by  stiffened  gussets  at  each  floor  beam  or  transverse 
strut. 

83.  Plate  girders   shall  be  cambered   y^"   for  each   25        camber. 
feet  in  length,  unless  otherwise  specified. 


IX.  STRINGERS  AND  FLOOR  BEAMS. 

84.  Stringers  shall  generally  be  placed  6  feet  6  inches, 
center  to  center;  shall  be  as  deep  as  practicable,  consistent 
with  economy,  and  shall  preferably  be  riveted  to  the  webs  of 
floor  beams. 

The  span  length  shall  be  taken  as  the  distance  between 
centers  of  floor  beams. 

85.  When  lengths  exceed  12  feet  or  twelve  times  flange 
widths,  stringers  will  have  their  upper  flanges   connected 
by  a  system  of  angle  bracing,  angles  to  be  not  less  than 
3-1^x3x5-16,  with  at  least  three  %  inch  rivets  in  connection. 
Cross  frames  to  be  placed  near  outer  ends  of  end  stringers. 


(19) 


Bracing  will  be  required  in  all  cases  where  alignment  is  on 
curve. 

86.  Floorbeams   will   be   riveted   to   the   webs   of   plate 
girders  or  to  the  posts  of  through  truss  bridges,  preferably 
above  the  pin  in  the  latter  case. 

The  span  length  shall  be  taken  as  the  distance  center  to 
center  of  trusses. 

Floorbeam  hangers  shall  be  avoided  when  possible.     (See 
paragraph  21.) 

87.  All   bridges    shall   preferably   have   end    floorbeams 
and  when  distance  from  center  of  end  floorbeams  to  back 
wall  equals  or  exceeds   18",  brackets  shall  be  provided  in 
line  with  stringers. 

88.  Connection   angles   of   stringers   to   floorbeams    and 
of  floorbeams  to  truss,  shall  not  be  less  than  3^x3^x9-16, 
and  the  webs  of  all  stringers  and  floorbeams  shall  be  faced 
true  and  square. 


Unsymmetrical 
Sections. 


H-Sections. 


Top  Laterals. 


X.  TRUSSES  AND  TOWERS. 

89.  Unsymmetrical   chord   sections    composed    of    two 
rolled  or  riveted  channels  and  one  plate  shall  be  so  propor- 
tioned that  the  centers  of  pins  in  abutting  members  shall  be 
in  the  same  line  and  the  eccentricity  may  be  made  sufficient 
to  counteract  the  bending  stress  due  to  the  weight  of  the 
member  or  provision  must  be  made  for  it,  as  in  top  chords 
and  end  posts.     The  material  shall  be  concentrated  mostly 
in  the  channels. 

90.  H-shaped  sections,  if  exceeding  ten  inches  in  depth, 
shall  have  tie  plates  at  ends  holding  them  truly  square. 

91.  The   top   lateral   struts   shall   be   of  the   full   depth 
of  the  chord  and  shall  be  securely  riveted  thereto.     The 
top  lateral   rods,  if  used,   shall  be  attached  to  the   lateral 
gusset  plates,  which   shall  be  securely   riveted  to  the  top 
chord. 


(20) 


92.  For  spans  of  200  feet  and  under,  each  portal  frame 
shall  consist  of  four  angles  riveted  to  the  end  posts  and 
connected  by  diagonal  latticing.     The  latticing  shall  be  flat 
bars  if  the  depth  of  the  portal  does  not  exceed  two  feet  and 
angles  if  of  greater  depth. 

For  spans  exceeding  200  feet  in  length  the  portal  frames 
/nay  consist  of  top  and  bottom  struts  connected  by  cross 
braces. 

93.  In  through  bridges,  when  the  depth  of  truss  is  be- 
tween 25  and  30  feet,  knee  braces  shall  be  used  at  each 
vertical  post;   when  the  depth   exceeds  30  feet   sub-struts 
and  overhead  diagonal  rods  or  lattice  struts  of  angles  shall 
be  used  at  each  vertical  post. 

94.  There  shall  be  built  or  cast  steel  bolsters  at  each  end 
of  span,  securely  anchored  to  the  masonry,  provision  to  be 
made  for  expansion.     Anchor  bolts  shall  be  set  in  Portland 
cement.      (See  paragraph   163.) 

95.  Long  tension  members  shall  be  clamped  together  at 
intersection  to  prevent  rattling.     Posts  and  struts  shall  be 
in  one  length  without  splice. 

96.  Struts    composed    of   two    channels     latticed     shall 
preferably  have  the  webs  of  the  channels  vertical  with  the 
clear  distance  between  webs  such  that  the  radius  of  gyration 
of  the  member  with  reference  to  an  axis  parallel  to  the  webs 
of  the  channels  shall  not  be  less  than  the  radius  of  gyration 
of   the  channels.      Provision   must   be   made   for   drainage 
where  necessary. 

97.  The   legs   of   trestle   bents   shall   generally   have   a 
batter  of  one  horizontal  to  six  vertical. 

98.  The  bents  shall  be  united  in  pairs  to  form  towers, 
and  each  tower  thus  formed  shall  be  thoroughly  braced  in 
all  directions.     Lateral  and  longitudinal  struts  shall  be  pro- 
vided at  bottom  and  at  each  intermediate  joint;  also  at  top 
in  the  absence  of  floorbeams  or  girders  acting  as  such. 

99.  Each  leg  shall  be  securely  anchored  to  its  pedestal, 
provision  being  made  for  expansion. 


Portals 


Cross  Bracing. 


Bolsters  and 
Anchors. 


Long  Members. 


Struts. 


Towers. 


(21) 


Chords. 


Eyebars. 


Camber. 


Eyebars  and 
Pins. 


100.  If  the  length  of  the  panel,   divided  by   the  least 
radius  of  gyration  of  the  top  chord  is  less  than  the  length 
of    span    divided   by   the    radius    of    gyration   of    the   top 
chords,  considered  as  a  trussed  column,  the  latter  shall  be 
used  in  finding  the  area  of  top  chord  sections. 

101.  Eye  bars  shall  be  closely  packed,  and  as  nearly  par- 
allel as  possible,  the  greatest  allowable  inclination  of  any 
bar  being  limited  to  i  inch  in  10  feet.     (See  paragraph  60.) 

1 02.  Screw  ends  of  pins  must  project  at  least  ^4"  be- 
yond nuts,  to  permit  upsetting  in  the  field. 

103.  Trusses  shall  have  just  sufficient  camber  to  bring 
the  joints  of  the  compression  chord  to  a  true  square  bear- 
ing when  the  truss  is  fully  loaded.     Each  member  of  the 
truss  shall  be  lengthened  or  shortened  in  proportion  to  the 
street  to  which  it  is  subject  under  a  full  dead  and  full  live 
load,  so  that  under  the  full  loading  each  member  will  be 
strained  to  its  normal  length. 

104.  The  center  of  bearings  of  the  stressed  members  are 
to  be  considered  as  the  points  of  application  of  loads  on 
pins  when  determining  bending  moments.    The  diameter  of 
the  pins  shall  not  be  less  than  £4  of  the  width  of  widest 
bar    attached.     Heads   of   eye    bars   must   not   be    less    in 
strength  than  body  of  bar. 


Sort  Steel. 


XI.  RIVETED  WORK. 

105.  All  holes  in  tension  members  of  all  thicknesses 
less  than  three-fourths  (%)  inch  shall  be  either  punched 
one-eighth  (*/&)  inch  smaller  than  the  rivet  required  and 
reamed  to  one-sixteenth  (1-16)  inch  larger,  or  they  may  be 
drilled  from  the  solid. 

1 06. .  All  holes  in  tension  members  of  all  thicknesses 
three-fourths  ($4)  inch  or  greater  shall  be  drilled  from 
the  solid. 

107.  All  holes  in  compression  members  of  all  thick- 
nesses less  than  three-fourths  (^4)  inch  shall  be  punched 
full  size. 


(22) 


1  08.  All  holes  in  compression  members  of  all  thick- 
nesses three-fourths  (24)  inch  or  greater  shall  be  drilled 
from  the  solid. 


109.     All  holes    in   metal   less   than   three-fourths    (%)        Medium  steel. 
inch  thick   shall  be  either  punched   one-eighth    (*^)    inch 
smaller  than  the  rivet  required  and  reamed  to  one-sixteenth 
(1-16)  inch  larger,  or  they  may  be  drilled  from  the  solid. 

no.  All  holes  in  metal  three-fourths  (fy)  inch  or 
greater  in  thickness  shall  be  drilled  from  the  solid. 

in.  Reamed  work  is  not  required  for  fillers,  lace  bars, 
transverse,  diagonal  or  lateral  bracing,  except  to  make  holes 
true  and  square  to  members. 

112.  When  plates  are  drilled  as  assembled,  they  must 
be  separated  after  being  drilled  and  cleaned  of  clippings 
forced  between  them  by  the  drill.    The  square  shoulders  of 
all  rivet  holes  under  rivet  heads  must  have  a  fillet  of  one- 
thirty-second  (1-32)  inch  neatly  removed. 

113.  Every  built  member  or  girder  must  be  true  and 
out  of  wind,  neatly  finished  to  length,  and  field  driven  rivets 
of  all  main  girder  connections  shall  be  laid  out  with  tem- 
plates and  accurately  drilled,  so  as  to  pass  the  rivets  cold. 

114.  Power  riveting  shall  be   used   wherever  possible. 
All  rivets  must  have  neatly  capped  full  heads.     Tightening 
loose  rivets  by  recupping  or  '  'setting  up"  will  not  be  al- 
lowed; they  must  be  cut  out  and  redriven,  whether  in  shop 
or  field.     Rivets  must  be  properly  heated  and  driven  to 
completely  fill  the  holes.     No  loose  rivets  allowed. 

See  paragraph  68.  Bolt8 


XII.  QUALITY   OF   MATERIAL. 
A.  WROUGHT  IRON. 

115.  Wrought  iron  shall  be  made  by  the  puddling 
process  or  rolled  from  fagots  or  piles  made  up  from  No. 
I  wrought  iron  scrap,  alone  or  with  muck  bar  added. 

(23) 


Manufacture, 


Physical 
Properties. 


Cold  Bending 
Tests. 


Nicking  Test. 


Hot  Bending 
Tests. 


Yield  Point. 


Finish. 


116.  The  minimum  physical  qualities  required  shall  be 
as  follows: 

Tensile  strength,  pounds  per  sq.  inch 48,000 

Yield   point,    pounds    per    sq.    inch... 25,000 

Elongation,  per  cent,  in  8  inches 20 

117.  In  sections  weighing  less  than  0.654  pounds   per 
lineal  foot  the  percentage  of  elongation  required  shall  be 
15  per  cent. 

1 1 8.  Cold  bending  tests  shall  be  made  on  specimens  cut 
from  the  bar  as  rolled.    The  specimen  shall  be  bent  through 
an  angle  of  180  degrees  by  a  succession  of  light  blows. 

119.  When  nicked  and  bent,  it  shall  show  a  generally 
fibrous  fracture,   free  from  course  crystalline  spots.     Not 
over  10  per  cent,  of  the  fractured  surface  shall  be  granular. 

1 20.  Hot  bending  tests  shall  be  made  on  specimens  cut 
from  the  bar  as  rolled.     The  specimens,  heated  to  a  bright 
red  heat,  shall  be  bent  through  an  angle  of  180  degrees  by 
a  succession  of  light  blows  and  without  hammering  directly 
on  the  bend. 

121.  If  desired,  a  bar  shall  be  worked  and  welded  in  the 
ordinary  manner  without  showing  signs  of  red-shortness. 

122.  The  yield  point  shall  be  determined  by  the  careful 
observation  of  the  drop  of  the  beam  or  halt  in  the  gauge  of 
the  testing  machine. 

123.  All    wrought   iron   must   be     practically     straight, 
smooth,  free  from  cinder  spots  or  injurious  flaws,  buckles, 
blisters  or  cracks.    As  the  thickness  of  bars  approaches  the 
maximum  that  the  rolls  will  produce  the  same  perfection 
of  finish  will  not  be  required  as  in  thinner  ones. 

In  flat  and  square  bars  one-thirty-second  (1-32)  inch 
variation  either  way  from  the  size  ordered  will  be  allowed. 

In  round  iron  one  one-hundredth  (i-ioo)  inch  variation 
either  way  from  the  size  ordered  will  be  allowed. 

B.  CAST    IRON. 

124.  Castings  shall  be  of  tough,  gray  iron,   free  from 
injurious  cold  shuts  or  blow  holes,  and  of  smooth,  work- 
manlike finish. 


(24) 


One  sample  bar,  one  inch  square,  about  five  feet  long,  cast 
in  sand  mould,  shall  be  furnished  from  each  cast.  This 
sample  bar  shall  be  capable  of  sustaining  on  a  clear  span 
of  four  and  one-half  (4.^2)  feet,  a  central  load  of  500 
pounds  when  tested  in  the  rough  bar. 

C.  WROUGHT   STEEL. 

125.  All  steel  shall  be  open  hearth,  made  at  works  of  es- 
tablished reputation,   which  have  been  successfully  manu- 
facturing steel  for  at  least  one  year. 

126.  If  made  in  an  acid  furnace,  the  amount  of  phos- 
phorous   and    sulphur    in    the    finished    product    shall    not 
exceed  eight  one-hundredths  (.08)  of  one  per  cent,  and  six 
one-hundredths   (.06)   of  one  per  cent.,  respectively. 

127.  If  made  in  a  basic  furnace,  the  amount  of  phos- 
phorus  or   sulphur    shall    not    exceed    six    one-hundredths 
(.06)  of  one  per  cent. 

128.  The  tensile  strength,  elastic  limit,  elongation  and 
reduction  of  area  shall  be  determined  from  a  standard  test 
piece  cut  from  the  finished  material  and  planed  or  turned 
parallel  for  at  least  ten  (10)  inches  of  its  length,  the  piece 
to  have  as  nearly  one-half  (J/£)   square  inch  sectional  area 
as  practicable,  and  the  elongation  to  be  measured  on  an 
original  length  of  eight  (8)  inches. 

Specimens  for  bending  tests  shall  be  cut  from  the  finished 
section  and  shall  be  of  the  same  form  as  those  used  for 
tensile  tests. 

129.  Three  specimens,  two  for  tensile  tests  and  one  for 
bending   test,    shall  be   furnished   from   each   melt,   except 
where  a  melt  is  rolled  into  widely  varying  sections,  when 
each  of  such  widely  varying  sections  shall  be  represented 
by  at  least  one  test. 

Where  only  a  small  portion  of  a  melt  is  rolled  into  the 
order  covered  by  these  specifications,  it  is  left  to  the  discre- 
tion of  the  engineer  or  his  authorized  representative  to 
reduce  the  number  of  tests. 


Kind. 


Acid  Open 
Hearth. 


Basic  Open 
Hearth. 


Test  Pieces. 


Number  of 
Tests. 


(25) 


Full  Size  Test. 


Grades. 


Medium  Steel. 


If  the  manufacturer  so  desires,  the  bending  tests  may  be 
made  on  the  broken  tensile  test  pieces  instead  of  on  speci- 
mens as  specified  above. 

130.  Eyebars  shall  be  of  medium  steel.     Full-sized  tests 
shall  show  twelve  and  one-half  (i2^4)  per  cent,  elongation 
in  fifteen  feet  of  the  body  of  the  eyebar,  and  the  tensile 
strength  shall  not  be  less  than  55,000  pounds  per  square 
inch.     Eyebars  shall  be  required  to  break  in  the  body,  but 
should  an  eyebar  break  in  the  head,  and  show  twelve  and 
one-half  (i2l/2)  per  cent,  elongation  in  fifteen  feet  and  the 
tensile  strength  specified,  it  shall  not  be  cause  for  rejection, 
provided  that  not  more  than  one-third   (1-3)   of  the  total 
number  of  eyebar s  tested  break  in  the  head. 

The  engineer  will  notify  the  contractor  of  the  number  of 
full  sized  eyebar  tests  required. 

All  bars  which  do  not  meet  the  requirements  of  the  speci- 
fications shall  be  at  the  expense  of  the  contractor,  all  others 
shall  be  paid  for  by  the  purchaser,  at  the  contract  price  of 
finished  metal  work  on  cars  at  shops,  less  the  scrap  value 
of  the  broken  bars.  (See  paragraph  161.) 

131.  Material   which   is  to  be   used   without   annealing 
or  further  treatment  is  to  be  tested  in  the  condition  in  which 
it  comes  from  the  rolls.     When  material  is  to  be  annealed 
or  otherwise  treated  before  use,  the  specimen  representing 
such  material  is  to  be  similarly  treated  before  testing. 


132. 
rivet. 


Steel  shall  be  of  three  grades:     Medium,  soft  and 


133.  Specimens  from  finished  material,  cut  to  size 
specified  above,  shall  have  an  ultimate  tensile  strength  of 
not  less  than  60,000  nor  more  than  70,000  pounds  per 
square  inch ;  and  elastic  limit  of  not  less  than  35,000  pounds 
per  square  inch,  and  an  elongation  of  not  less  than  twenty- 
two  (22)  per  cent. 

This  grade  of  steel  to  bend  cold  180  degrees  over  a 
mandrel,  the  diameter  of  which  is  equal  to  the  thickness  of 
the  piece  tested,  without  a  crack  or  flaw  on  the  outside  of 
the  bent  portion. 


(26) 


134-  Specimens  from  finished  material,  cut  to  size  speci- 
fied above,  shall  have  an  ultimate  tensile  strength  of  not 
less  than  52,000  nor  more  than  62,000  pounds  per  square 
inch  ;  and  an  elastic  limit  of  not  less  than  32,000  per  square 
inch;  and  an  elongation  of  not  less  than  twenty-five  (25) 
per  cent. 

This  grade  of  steel  must  stand  bending  cold  180  degrees 
and  close  down  flat  on  itself  without  sign  of  fracture  on 
convex  side  of  curve. 

135.  Specimens   cut  to  size   specified   above  shall   have 
an   ultimate  tensile   strength  of  not  less   than   50,000   nor 
more  than  60,000  pounds  per  square  inch;  an  elastic  limit 
of  not  less  than   30,000  pounds  per  square   inch,   and   an 
elongation  of  not  less  than  twenty-six  (26)  per  cent. 

136.  All  blooms,  billets  or  slabs  shall  be  examined  for 
surface  defects,  flaws  or  blow  holes  before  being  rolled  into 
the  finished   sections,   and   such   chippings   and   alterations 
made  as  will  insure  solidity  in  the  rolled  sections. 

137.  Every  finished  piece  of  steel  shall  be  stamped  with 
the  melt  number,  and  steel  for  pins  shall  have  the  number 
stamped  on  the  ends.     Rivet    and  lacing  steel,  and  small 
pieces  for  pin  plates  and  stiffeners,  may  be  shipped  in  bun- 
dles, securely  wired  together,  with  the  melt  number  on  a 
metal  tag  attached. 

138.  The    chemical    analysis    for    carbon,    phosphorus 
and  sulphur  of  each  melt  must  be  furnished  to  the  engineer 
or  his  representative  at  the  mill,  before  any  of  the  material 
rolled  from  said  melt  is  shipped  from  the  mill. 

139.  Finished  material  must    present    a    smooth,  clean 
surface,  free  from  cracks,  buckles,  flaws,  ragged  edges,  or 
any  other  defects,   and  must  be   straight  throughout   and 
true  to  section. 


Soft  Steel. 


140.     A  variation  of  more  than  two  and  one-half 
per  cent,  from  ordered  weight  will  be  considered  cause  for 
rejection. 


Rivet  Steel. 


Chippings  and 
Alterations. 


Branding. 


Chemical 
Analysis. 


Finish. 


Variation  in 
Weight. 


(27) 


Shipments. 


Quality  of 
Paint. 


For  all  plates  ordered  to  gauge,  there  will  be  permitted  an 
average  excess  of  weight  over  that  corresponding  to  the 
dimensions  on  the  order  equal  in  amount  to  that  specified  in 
following  table: 


WIDTH  OF  PI,ATE. 

THICKNESS  OF 

PIRATE. 
Inch. 

Up  to  75  inches. 

75  to  100  inches. 

Over  TOO  inches. 

Per  cent. 

Per  cent. 

Per  cent. 

X 

10 

14 

18 

5-i6 

8 

12 

16 

ft 

7 

10 

13 

7-16 

6 

8 

10 

Yz 

5 

7 

9 

9-16 

4^ 

6)4 

8>£ 

H 

4 

6 

8 

Over         ^ 

3/3 

5 

61/2 

141.  Shipments  of  material  from  the  mills  will  not  be 
permitted  until  after  the  tests  have  been  made.     Copies  of 
all  shipping  invoices  must  be  furnished  to  the  engineer  or 
his  representative  at  the  mill  as  shipments  are  made. 

D.  CAST   STEEL. 

142.  Steel  castings  shall  be  made  of  a  firs^  class  quality 
of  open-hearth  steel,   sound,  smooth,  true  to  pattern,  and 
free  from  blow  holes,  flaws  and  warps.     All  steel  castings 
shall  be  thoroughly  annealed  at  a  temperature  sufficiently 
high  to  make  a  blue  scale,  and  when  tested  in  three-quarter 
(24)   inch  round  turned  test  pieces,  cut  from  castings,  or 
from  extensions  cast  to  the  castings,   shall  show  an  ulti- 
mate strength  of  from  65,000  to  75,000  pounds  per  square 
inch,  and  an  elongation  of  not  less  than  fifteen   (15)   per 
cent,  in  two  (2)  inches,  and  including  the  break. 

E.  PAINT. 

143.  All  paint  for  use  in  the  "first  coat"  shall  be  of  the 
best  quality  of  graphite   paint  or  of  carbon  primer,  of  a 
manufacture  acceptable  to  the  engineer. 


(28) 


144-     All  paint  for  use  in  the  "finish  coats"  shall  be  of 
a  quality  and  color  specified  on  the  second  page  hereof. 

145.  All  surfaces  that  are  inaccessible  after  being  riv- 
eted,  or  after  erection,    shall   have,   before   assembling  or 
before  erection,  two  (2)  coats  of  pure  red  lead  and  boiled 
linseed  oil,  mixed  in  the  proportion  of  eighteen  (18)  Ibs.  of 
lead  to  one  (i)  gallon  of  oil. 

All  bolts  which  are  to  remain  permanently  in  the  struc- 
ture are  to  be  dipped  in  "first  coat,"  as  described  above. 

146.  As  soon  as  shop   work   is  complete,  the  material 
shall  be  thoroughly  cleaned  from  all  scale,  rust,  grease  or 
other  foreign  matter,  and  given  one  coat  of  "first  coat,"  as 
described  above. 

147.  Erection  marks  shall  be  made  on  the  painted  sur- 
face and  not  on  the  bare  metal  and  then  oiled  over. 

148.  After  erection  and  before  applying  the  finish  coats, 
the  material  shall  again  be  retouched  and  field  rivets  shall 
be  painted  with  the  "first  coat,"  as  described  above;  the 
field   rivets   shall   be  painted   as   soon  as   practicable   after 
driving. 

149.  All  metal  work  shall,  after  erection,  be  thoroughly 
cleansed  from  mud,  grease  or  any  other  objectionable  ma- 
terial that  may  be  found  thereon  (wire  brushes  or  scrapers 
shall  be  used  when  necessary  or  required  by  the  engineer), 
and  painted  with  two  (2)   coats  of  "finish  coat,"  as  speci- 
fied above. 

No  painting  will  be  allowed  in  wet  or  freezing  weather, 
and  all  surfaces  must  be  dry  when  paint  is  applied. 


Inaccessible 
Surfaces. 


First  Coat. 


Erection  Marks. 


Retouching  and 
Finish  Coats. 


Finishing 
Coats. 


150.  All  turned  or  planed  surfaces  shall  be  coated  with 
a  mixture  of  white  lead  and  tallow  before  being  exposed 
to  the  weather. 

151.  All  paint  and  oil  used  for  the  structure  shall  be 
especially   purchased,   and  the  contractor  will   furnish   the 
engineer  with  copies  of  all  orders  for  same;  and  until  all 


Turned  and 

Planed 

Surfaces. 


Copies  of 
Orders. 


(29) 


such  copies  have  been  received  by  the  engineer,  no  paint 
shall  be  applied. 


F.  TIMBER. 

152.  All  timber  shall  be  of  the  best  quality  of  the  kind 
specified,  cut  from  sound,  live  timber,  free  from  loose  or 
rotten  knots,  worm  holes,  wind  shakes  or  splits,  reasonably 
well  seasoned,  straight  grained,  square  edged,  and  free 
from  any  defect  calculated  to  impair  its  strength  or  dura- 
bility. Sap  wood  shall  not  be  allowed  in  more  than  ten 
(10)  per  cent,  of  the  pieces  of  one  kind,  and  no  piece 
will  be  accepted  showing  sap  covering  more  than  one-fourth 
(/4)  the  width  of  the  piece  on  any  face  at  any  point,  nor 
more  than  half  the  thickness  of  any  plank  at  its  edge,  at 
any  point. 


Annealing. 


Appearance. 


XIII.  WORKMANSHIP. 

153!     All  workmanship  must  be  strictly  first  class. 

154.  All  members  that  may  become  bent  or  in  any  way 
injured  in  transportation  or  erection,  or  from  any  cause, 
must  be  repaired,  straightened  and  made  good  to  the  satis- 
faction of  the  engineer. 

155.  All  plates  and  shapes  shall  be  carefully  straightened 
before  the  work  is  laid  out,  and  all  work  must  be  finished  in 
a  neat  and  workmanlike  manner.     The  edges  of  sheared 
steel  plates  in  main  members  shall  be  carefully  faced  or 
planed  to  effectively  remove  defects  caused  by  shearing. 

156.  No  forging  or  other  work  must  be  performed  on 
any  material  at  a  temperature  as  low  as  a  blue  heat,  and 
all  steel  forged  work  must  be  afterward  thoroughly   and 
uniformly  annealed  by   heating  throughout  to  a  uniform 
dark  red  heat  and  being  allowed  to  cool  slowly. 

157.  Due  regard  must  be  had  for  the  neat  and  attractive 
appearance  of  the  finished  structure;  and  details  of  work- 
manship of  an  unsightly  character  will  not  be  allowed. 

(30) 


XIV.  INSPECTION  AND  TESTS. 

158.  All  material  shall  be  subject  to  inspection  and  tests 
at  mills  and  shops  during  the  various  processes  of  manu- 
facture, and  free  access  must  be  permitted  for  the  Railway 
Company's  engineer  or  inspectors  at  any  works  where  ma- 
terial is  in  process  of  manufacture.     A  notice  of  at  least 
one  week  must  be  given  to  the  Railway  Company  when  its 
inspector  may  be  on  hand  for  the  performance  of  his  duties. 

159.  All  materials  and  workmanship  shall  be  subject  to 
inspection    and   rejection    of   the   Railway    Company's    en- 
gineer; and  all  materials  condemned  by  him  shall  be  imme- 
diately removed  from  the  work. 

1 60.  The  inspection  of  the  work  shall  not  relieve  the 
contractor  of  his  obligation  to  perform  sound  and  reliable 
work,  as  herein  provided.     And  all  work  of  whatever  kind 
which,  during  its  progress,  and  before  it  is  finally  accepted 
may  become  damaged  from  any  cause,  shall  be  replaced  by 
good,  sound  work,  satisfactory  to  the  Railway  Company's 
engineer. 

161.  The  contractor   shall   furnish  the  engineer  or  his 
inspector  all  necessary  facilities  for  making  the  tests  speci- 
fied herein. 


Mill  and  Shop 
Inspection. 


Inspection  not 
to  Relieve 
Contractor. 


XV.  ERECTION. 

162.  The  contractor  shall  erect  the  bridge  complete,  in 
a  thoroughly  workmanlike  manner  and  ready  for  the  ties, 
and  to  the  lines  and  grades  furnished  by  the  Railway  Com- 
pany's engineer. 

163.  The  contractor  for  superstructure  shall  furnish  and 
put  in  place  all  stone  bolts  and  anchors  for  attaching  the 
iron  or  steel  work  to  the  masonry.     He  will  drill  all  the 
necessary  holes   in  the  masonry  and  set  all  bolts  in  neat 
Portland  cement  of  a  brand  satisfactory  to  the  -Railway 
Company's  engineer.     When  the  requirements  of  the  con- 
tract demand  that  the  bolts  or  anchors  be  built  in  the  ma- 
sonry the  contractor   for  the  superstructure  shall   furnish 

(30 


Erection. 


Anchor  Bolts. 


Lines,  Grades, 
Etc. 


Unloading. 


False  Work. 


Permits  and 
Licenses. 


Damages. 


said  bolts  and  anchors  and  deliver  them  at  the  bridge  site 
at  such  time  as  may  be  ordered  by  the  Railway  Company's 
engineer,  but  he  will  not  be  required  to  place  them.  (See 
paragraph  15.) 

164.  All  lines  and  grades  are  to  be  given  by  the  Railway 
Company's  engineer. 

165.  The  stakes  and  marks  given  by  the  Railway  Com- 
pany's engineer  must  be   carefully  preserved  by  the  con- 
tractor, who  shall  give  the  engineer  all  necessary  assistance 
and  facilities  for  the  establishment  of  the  lines  and  grades, 
and  the  measuring  up  of  the  work. 

1 66.  All  material  shall  be  unloaded  at  the  bridge  site 
with  care  and  piled  on  skids  well  above  the  level  of  the 
ground. 

167.  The   contractor   shall   furnish   and   erect   all    false 
work,  staging  and  scaffolding,   and  all  tools  and  erection 
plant  necessary  to  do  the  work  thoroughly  and  expediti- 
ously,  and  he  shall  remove  the  same  as  fast  as  the  advance 
of  the  work  will  permit. 

1 68.  Before  placing  any  false  work,  the  contractor  shall 
submit  to  the  engineer  for  his   approval,   duplicate  draw- 
ings, showing  the  location  of  all  bents,  and  the  placing  of 
falsework  other  than  such  as  is  approved  shall  not  be  al- 
lowed. 

169.  The  contractor  shall  give  to  the  proper  authorities 
all  requisite  notices  relating  to  the  work  in  his  charge,  and 
obtain  all  official  permits  and  licenses   for  temporary  ob- 
structions, and  pay  all  proper  fees  for  same ;  and  he  shall 
pay  "for  any  other  legal  charges  from  city,  town  or  county 
officers. 

170.  The  contractor  shall  pay  all  damages  or  losses  or 
claims  recovered  that  the  owner  may  be  made  liable  for, 
and  save  the  owner  harmless  in  all  things  from  any  acci- 
dent   which    may    happen    or    arise    by    reason    of    failure, 
neglect  or  refusal  on  his  part  or  that  of  anyone  in  his  em- 
ploy to  take  all  necessary  precaution  to  prevent  the  same, 


(32) 


and  also  arising  from  any  and  all  encroachments  or  tres- 
passing on  the  neighboring  property. 

171.  All  refuse  material  and  rubbish  that  may  accumu- 
late during  the  progress  of  the  work  shall  be  removed  from 
time  to  time,  and  upon  completion  of  the  work  all  surplus 
material,  falsework  and  rubbish  shall  be  removed  from  the 
vicinity  of  the  structure  as  may  be  directed  by  the  Railway 
Company's  engineer. 

172.  When  the  erection  is  done  by  the  Railway  Com- 
pany, the  contractor  shall  furnish  all  necessary  pilot  nuts 
for  erection,  to  be  returned  to  contractor  in  as  good  condi- 
tion as  when  received,  when  erection  is  completed. 


Refuse  Material 
and  Rubbish. 


XVI.  NAME   PLATES. 

173.  Two  name  plates  of  suitable  size  and  design,  and 
which  may  be  required  to  be  of  aluminum  or  bronze,  shall 
be  provided  and  securely  fastened  at  points  to  be  designated 
by  the  engineer.  The  plates  shall  be  inscribed  as  directed 
by  the  engineer. 


XVII.  GENERAL. 

174.  The  structure  shall  be  built  under  the  direction  of 
the   engineer   in   charge,   in  accordance   with   the   general 
drawings,   and   will  include  all  work  of  any   description, 
whether  specifically  set  forth  herein  or  on  the  drawings,  or 
not,  to  make  the  work  herein  provided  for  complete,  to  the 
entire  satisfaction  of  the  Railway  Company. 

175.  All  fees  or  royalties  for  any  patented  invention, 
article  or  arrangement  that  may  be  used  upon  or  in  any 
manner  connected  with  the  construction,   erection  of  the 
work,  or  any  part  thereof,  embraced  in  these  specifications, 
shall  be  included  in  the  price  mentioned  in  the  contract ;  and 
the  contractor  shall  protect  and  hold  harmless  the  Railway 
Company  against  any  and  all  demands  for  such  fees,  roy- 
alties or  claims,  and  before  the  final  payment  or  settlement 
is  made  on  account  of  the  contract,  the  contractor  must 

(33) 


Patented 
Devices. 


Subletting 


Employees. 


Changes. 


furnish  acceptable  proof  of  a  proper  and  satisfactory  re- 
lease from  all  such  claims. 

176.  No  part  of  the  work  shall  be  sublet,  nor  shall  the 
contract  for  the  whole  or  any  portion  of  the  work  be  as- 
signed unless  by  written  consent  of  the  Railway  Company's 
engineer. 

177.  Should  any   disorderly   or  incompetent   person  be 
employed  upon  the  work,  he  shall  upon  notice   from  the 
Railway  Company's  engineer  be   discharged   and  not  em- 
ployed again  without  his  permission. 

178.  The  work  shall  be  done  substantially  in  accordance 
with  the  accepted  plans,  details  and  directions  by  the  en- 
gineer, and  in  accordance  with  these  specifications,  but  the 
right  is  reserved  by  the  Railway  Company,  without  incur- 
ring any  liability   therefor,   to  make  such  changes   in   the 
said  general  or  detail  plans  and  in  the  specifications  as  its 
engineer  may  deem  necessary   for  the  convenience,   safety 
and  stability  of  the  work,  or  as  shall  be  deemed  advisable 
or  desirable  by  him,  to  make  the  same  a  satisfactory  piece 
of  work. 

179.  The  right  is  also  reserved  by  the  Railway  Com- 
pany, without  incurring  any  liability  therefor,  beyond  the 
contract  price,  except  as  hereinafter  provided,  to  increase 
or  diminish  the  amount  of  labor  or  material,  or  both,  herein 
provided  for,  within  s'uch  limits  as  shall  be  deemed  neces- 
sary by  said  engineer  to  make  said  work,  when  completed, 
a  satisfactory  piece  of  work. 

1 80.  But  if  any  such  change  in  any  of  the  said  general 
or  detailed  plans,  or  in  the  specifications,  shall,  in  the  opin- 
ion of  the  Railway  Company's  engineer,  materially  increase 
the  actual  cost  of  performing  the  labor  necessary  to  con- 
struct the  portions  of  the  work  thereby  changed,  beyond 
what   such   labor   would   have  cost,   if  performed   without 
such  change,  then  the  contractor  shall  receive  the  amount 
of  such  increased  cost,  as  determined  by  the  engineer,  with 
ten  (10)  per  cent,  thereof  additional,  such  percentage  to  be 
for  and  in  lieu  of  profits ;   any   decrease  in  such   cost,  as 


(34) 


determined  by  the  engineer,  shall  inure  to  the  benefit  of  the 
Railway  Company. 

181.  And  if  by  any  such  change  in  any  of  the  said  general 
or  detail  plans,  or  in  these  specifications,  any  material  is 
used  in  the  structure,  the  cost  of  which  is,  in  the  opinion  of 
the  Railway  Company's  engineer,  in  excess  of  that  herein 
provided  for,  the  contractor  shall  receive  such  excess  of  cost, 
as  determined  by  the  said  engineer,  and  ten  (10)  per  cent, 
thereof  additional,  such  percentage  to  be  for  and  in  lieu  of 
profits;  any  decrease  of  such  cost,  as  determined  by  said 
engineer,  shall  inure  to  the  benefit  of  the  Railway  Company. 

182.  The  contractor   shall   make   no  claim   against   the 
Railway  Company  for  damages  or  losses  occasioned  by  the 
elements  or  from  any  causes  for  which  the  Railway  Company 
is  not  responsible.    No  claim  for  extra  work  not  provided  for 
in  the  plans  and  specifications  will  be  allowed  unless  a  written 
order  to  perform  such  work  shall  have  been  given  by  the 
Railway  Company's  engineer,  and  all  claims  for  such  work 
shall  be  presented  in  writing  for  settlement  in  the  monthly 
estimate  next  after  such  work  shall  have  been  performed. 
Claims  by  the  contractor   for  damages   by   reason  of  any 
detention  on  the  part  of  the  Railway  Company  will  not  be 
allowed,  but  any  such  detention  shall  make  a  corresponding 
extension  of  the  time  for  completion  of  the  contract. 

183.  The  work  herein  provided  for  shall  be  commenced 
upon  any  part  or  portion  of  the  same,  as  the  Railway  Com- 
pany's engineer  may  direct,  within  ten  (10)  days  after  re- 
ceipt of  written  notice  from  the  engineer  so  to  do. 

184.  The  work  shall  be  prosecuted  continuously  and  in 
the  most  energetic,  expeditious  and  workmanlike  manner, 
with  the  largest  force  of  all  classes  of  workmen  that  can  be 
worked  to  advantage,  and  the  contractor  shall  supply  suffi- 
cient plant  to  work  at  such  places  and  at  as  many  places  as 
the  Railway  Company's  engineer  may  direct  until  the  whole 
shall  have  been  completed  ;  or  work  upon  any  part  or  portion 
of  the  structure  shall  at  any  time  be  wholly  or  partially 
suspended  or  discontinued  by  order  of  the  engineer,  when- 


Claims. 


Commencement 
of  Work. 


Prosecution 
of  Work. 


(35) 


ever  in  his  opinion  the  best  interests  of  the  owner  or  the 
progress  of  the  work  upon  other  parts  or  portions  of  the 
structure  may  demand  it. 

Completion  185.     The  entire  work  herein  provided  for  shall  be  prose- 

cuted in  such  manner  that  the  whole  shall  be  complete  and 
ready  for  acceptance  by  the  Railway  Company  at  or  before 
the  time  specified  on  the  first  page  hereof,  or  in  the  event 
that  the  contractor  fail  to  complete  the  work  within  such 
specified  time,  he  will  be  liable  for  any  and  all  damage 
which  the  Railway  Company  may  suffer  in  consequence  of 
the  delay ;  provided  that  any  mutual  agreement,  set  forth  in 
the  contract  of  which  these  specifications  form  a  part,  relat- 
ing to  damages  for  delay  of  completion  after  the  specified 
time  or  to  awards  for  completion  before  the  specified  time, 
shall  be  and  remain  in  full  force  and  effect. 

1 86.  If  at  any  time  during  the  progress  of  the  work  it 
should  appear  by  the  report  of  the  engineer  that  the  force 
employed,  the  quantity  or  quality  of  tools  or  appliances 
provided,  or  that  the  progress  or  character  of  the  work  or 
material  furnished  are  not  respectively  such  as,  in  the  opinion 
of  the  engineer,  will  insure  the  completion  of  the  work  under 
this  contract  within  the  time  specified,  or  not  in  accordance 
with  the  specifications,  then  in  that  case  the  Railway  Com- 
pany may  serve  written  notice  on  the  contractor  and  sureties 
to  at  once  supply  such  increase  of  force,  appliances  or  tools, 
and  to  cause  such  improvement  to  be  made  in  the  character 
of  the  work  or  materials,  as  will  be  required  to  make  the 
same  conform  to  these  specifications  and  the  requirements 
of  the  engineer;  and  if,  on  the  expiration  of  three  (3)  days 
after  the  service  of  such  written  notice  upon  the  contractor 
and  sureties  personally,  or  by  leaving  same  or  mailing  same 
for  them  at  la&t  known  addresses,  the  contractor  shall  have 
failed  to  furnish  to  the  Railway  Company  satisfactory  evi- 
dence of  his  efforts,  ability  and  intentions  to  remedy  the 
specified  deficiencies,  the  Railway  Company  may  thereupon 
erter  and  take  possession  of  the  said  work  or  any  part  there- 
of, with  tools,  materials,  plant,  appliances,  houses,  machinery 

(36) 


and  other  appurtenances  thereon,  hold  the  same  as  security 
for  any  and  all  damage  or  liabilities  that  may  arise  by  reason 
of  the  nonfulfillment  of  this  contract  within  the  time  speci- 
fied, and,  furthermore,  may  employ  the  said  tools  and  other 
appurtenances,  materials,  and  such  other  means  as  it  may 
deem  proper  to  complete  the  work  at  the  expense  of  the 
contractor,  and  may  deduct  the  cost  of  the  same  from  any 
payment  then  due  or  thereafter  falling-  due  to  the  contractor 
for  this  work ;  and,  in  case  the  contractor  shall  not  complete 
the  work  within  the  time  specified,  and  the  Railway  Company 
shall,  notwithstanding  such  failure,  permit  the  contractor 
to  proceed  with  and  complete  the  said  work  as  if  such  time 
had  not  elapsed,  said  permission  shall  not  be  deemed  a  waiver 
in  any  respect  by  the  Railway  Company  of  any  forfeiture  or 
liability  for  damages  or  expenses  thereby  incurred,  arising 
from  such  non-completion  of  said  work  within  the  specified 
time,  but  such  liability  shall  continue  in  full  force  against 
the  contractor  and  his  sureties  as  if  such  permission  had  not 
been  given. 

187.  Approximate  estimates  will  be  made  monthly  by  the 
Railway  Company's  engineer  if  requested  by  the  contractor, 
upon  the  amount  of  acceptable  material  delivered  at  the 
bridge  site  or  erected  in  place,  and  also  reasonable  estimates 
will  be  allowed  at  the  discretion  of  the  engineer  upon  ac- 
cceptable    material    delivered    at    the    shops    in    reasonable 
amounts  and  proper  condition. 

Ninety  (90)  per  cent,  of  the  amounts  of  such  estimates 
will  be  paid  in  cash  within  fifteen  (15)  days  after  approval 
of  such  estimates  by  the  Railway  Company  provided  no  legal 
restraints  are  placed  upon  such  owner  preventing  such  pay- 
ment. The  remaining  ten  (10)  per  cent,  will  be  paid  within 
fifteen  days  after  the  final  completion  and  acceptance  by  the 
Railway  Company  of  all  the  work  herein  specified,  provided 
the  same  is  free  from  all  claims  for  labor  and  material  under 
these  specifications,  which  might  in  any  manner  become  a  lien 
upon  said  structure  or  a  claim  upon  the  Railway  Company. 

1 88.  The  contractor  shall  be  required  to  comply  with  all 
federal,  state,  city,  town  or  other  laws  and  statutes  in  force  in 


Estimates  and 
Payments. 


Comply  with 
All  Laws. 


(37) 


Special 
Clauses. 


Plans  and 
Specifications. 


Engineer. 


the  locality,  and  it  is  understood  and  agreed  that  the  contract 
of  which  these  specifications  are  a  part,  is  made  and  executed 
subject  to  the  terms  and  conditions  of  any  and  all  such  laws. 
The  contractor  will  be  expected  to  inform  himself  regarding 
such  laws,  and  to  govern  himself  accordingly. 

189.  All  the  written  part  of  these  specifications  and 
any  special  clauses  attached  hereto,  and  referring  to  this 
structure,  are  to  be  considered  as  a  part  hereof,  and  shall  be 
as  carefully  noted  and  as  strictly  followed  as  if  printed 
herein. 

190.  The  plans  and  specifications  are  intended  to  be  ex- 
planatory of  each  other,  but  should  any  discrepancy  appear, 
or  any  misunderstanding  arise  as  to  the  import  of  anything 
contained  in  either,  the  interpretation  of  the  Railway  Com- 
pany's engineer  shall  be  final  and  binding  on  the  contractor ; 
and  all  directions  and  explanations  required,  alluded  to  or 
necessary  to  complete  any  of  the  provisions  of  these  specifi- 
cations,  and  give  them   due  effect,   will  be  given   by  the 
engineer. 

191.  The  term  "  engineer,"  as  herein  used,  is  understood 
to  mean  the  chief  engineer  in  charge  of  the  work,  and  the 
work  at  all  times  shall  be  under  his  control,  and  the  decisions 
of  said  engineer  upon  all  questions  as  to  estimates  or  the 
determination  of  the  quantity  or  quality  of  the  work,  and 
on  all  other  questions  herein  left  to  his  discretion,  shall  be 
final  and  conclusive. 


The  above  constitute  the  specifications  referred  to  in  the 
contract  of  the  undersigned  with 


dated  

Contracting  firm 
Bv   , 


(38) 


Ra 


Appendix  B, 


o 


CONVENTIONAL  SIGNS  FOR  BRIDGE  RIVETS. 

Shop.  Field. 

/ 

Two  Full  Heads. 


Countersunk  Inside  and  Chipped. 

Countersunk  Outside  and  Chipped. 

Countersunk  both  Sides  and  Chipped. 


o 


Flattened  to}£"  high  or  Countersunk 
and  not  Chipped. 


Flattened  to  tf"  high. 


Flattened  to  y%»  high. 


Inside.         Outside.     Both  Sides. 

<DO<D 
ODO 
0 


^  x 

H 


29260 


33.300 


£0000 
S0O00 

2500O 


32S00 


S0000 


J0000 
3S000 


26000 

4O000 
10OOO 
4OOOO 
-400O0 

20000 

26000 
26000 
26000 
26000 

40000 
40000 
40000 
40000 

20000 


/9S00 

3OOOO 
3OOOO 
3OOOO 
30O0O 


3000C 
&000O 
30000 

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UNIVERSITY  OF 


CALIFORNIA  LIBRARY 


1£*AY  USE 

RETURfcUrtl  DElWFROM  WHICH  BORROWED 


ETUlp^TA  DESpFRC 

JiM-teiN 


ENEWALS  ONLY — TEL  NO.  647-3405 
is  book  is  due  on  the  last  date  stamped  below,  or 

on  the  date  to  which  renewed. 
Renewed  books  are  subject  to  immediate  recall. 


INTER-LIBRARY 
LOAM 


SEP  11  1970 


SENT  ON  ILL 


JUN29 


U.  C.  BERKELEY 


SENT  ON  ILL 


JUN22 


'A-eOnvS.'TO 


(N5382slO)476-A-32 


General  Lib' 
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Berkel 


Cr 


